Homesteading Refrigerator to Die With –Part 5 – Passively Conducting Heat

Posted on July 9, 2018 by mcpletcher — 1 Comment

Now that we’ve covered the desire to build a well insulated refrigerator and freezer, as well as the advantages associated with living in a cold climate where ice can be produced passively, it’s time to move on to the detail of what a refrigerator system might just look like, and talk abut ways in which the idea can be expanded to improve the performance of actively powered freezers.

Two-Phase Thermosiphons (TPTS)

First, we have to talk about the operation and principles of a TPTS, and the difference with a Heat Pipe.  Both of these devices are forms of heat conductors.  Heat naturally flows from regions of a higher temperature to regions of a lower temperature.  Metals are a common choice for this- copper and aluminum being two of the more commonly selected, although other metals can be used depending on the environmental conditions present.  Metals are well known as effective conductors of heat, but the larger the distance between the heat source and heat sink, the larger the temperature difference necessary in order to conduct a given heat load.  Many applications, such as the cooling of integrated computer chips, require the lowest temperatures practicable at the source of heat, and the distance to the heat sink can be a few centimeters, to even more than a meter away.  Metals alone are not always suitable, so other methods have been developed.

Counterflow TPTS

A sealed metal pipe (assumed copper from here on out) containing a a volatile refrigerant at saturation, can conduct heat far better than the metal alone.  A simple example would be a one meter copper pipe, sealed with a few grams of  r134a refrigerant inside.  In a slightly vertical orientation, heat applied to the lower end of the pipe will first be absorbed by the copper, and then conducted to the the liquid refrigerant that naturally settles there.  Some of the liquid evaporates, raising the internal pressure of the pipe.  Refrigerant vapor higher up in the pipe, now at a higher pressure, will warm to a temperature slightly greater than the copper walls which are cooler than are found below where the heat is applied.  The copper walls absorb some latent heat, and the vapor is condensed, falling by gravity back to the bottom, where it can pick up heat and begin the process again.  Localized pressure differences between the heating region and the cooling region cause vapor to move from hotter to colder areas.  The more of the un-heated pipe which is exposed to the ambient air, the lower the temperature it will reach, and the lower the overall pressure the pipe will reach.  If only the top few centimeters are to dissipate heat (the condenser), the middle section can be insulated, such that very limited heat is dissipated in this region (or adiabatic region).  By adding additional heat exchange surface area to the condenser end, passing air or another cooling fluid across it, the heat source can be held at a lower temperature than it otherwise would without the additional design features.  Also, the surface area of the heat source region (or evaporator) can be improved with added fins, and increased internal surface area- conducting heat into the liquid more effectively and with a smaller temperature difference.

The device is a Counterflow Two-Phase Thermosiphon.  Two phases (vapor up and liquid down) flow in opposite directions in a common pipework.  They can interact with one another, impeding smooth flow, and increasing the temperature difference (delta T) the device operates at for a given heat load and operating conditions.  Gravity is essential for good operation, and is why these are sometimes referred to as Gravity Assisted Heat Pipes.  They only work if the condenser region is Read more ›

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Posted in Refrigeration, Refrigerator

Homesteading Refrigerator to Die With –Part 4– The Scott Nielsen Ice Refrigerator

Posted on July 8, 2018 by mcpletcher — 2 Comments

Article from “Rodale’s New Shelter”, July-August, 1981

Zoom your browser in to make it easier to read!

 

 

Up Next

We’ll be getting into the design considerations of two-phase thermosiphons, building a passive refrigerator, and other opportunities with having freeze ice.

Homesteading Refrigerator to Die With –Part 5– Passively Conducting Heat

-M.C. Pletcher

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Posted in The Squatch

Homesteading Refrigerator to Die With –Part 3– Passive Winter Ice

Posted on July 8, 2018 by mcpletcher — 2 Comments

In the late 19th century, and first half of the 20th, ice refrigerators were a common feature in American households.  Blocks of ice could be purchased every few days and placed in an insulated box to slow the decay of foodstuffs.  The length of time between new blocks varied according to the size of the block, ambient conditions, condition and effectiveness of the refrigerator, and the economic access afforded to the household.  By and large, production of ice was first accomplished through the natural winter freezing of lakes and ponds in the northern latitudes, where it would then be scored, cut, and hauled into insulated warehouses and then distributed to customers.  This practice would continue well into the 20th century, but would eventually be supplanted by the mechanical production of ice with vapor compression or absorption machines, then altogether with the advent of affordable domestic mechanical refrigerators.  Very few individuals still utilize ice to for everyday home refrigeration needs.

Advantages to Living in a Cold Climate

As a means to provide home refrigeration without the assistance of industry, harvesting naturally produced ice in the winter, and using it throughout the year is certainly an option, but the region of southwestern Pennsylvania I am from doesn’t typically get cold enough, or for long enough, to freeze bodies of water to a thickness where sizable blocks could be cut.  An insulated storeroom would have to be of a size to hold a years worth of ice.  Also, there is the potential issue of refrigerator temperatures peaking higher than the target temperature of 4 degrees C.  Ice typically melts around 0 degrees, so such a small temperature difference would have to be maintained with ample refrigerator insulation, and well designed air circulation.

Nonetheless, some of these problems are solvable by looking at the problem with fresh eyes.  I believe there are great opportunities that come with low outdoor temperatures for a few months out of the year.  Dissipating latent heat from a substance like water, and in large enough quantities, then storing the “charged” phase change material, can have the effect of caching cold wintry conditions where food keeps longer, for use in high ambient conditions when it doesn’t.  Furthermore, this “ice bank” could drastically improve the performance of mechanical refrigeration systems as the discharge heat of these machines would be very effectively cooled by ice, only to later be dissipated to cold winter air.  Essentially, we’re talking about temporal heat displacement for refrigeration.

Examples of Prior Work

Natural ice harvesting was described above, and represents the best (and most developed) example of this, but we’re going to move beyond that.

Various studies, and actual installations have been performed to establish effective ways to offset annual heating and cooling loads on homes and commercial buildings.  These typically include a reversible heat pump which extracts latent heat from water to make ice and heat the building in the winter, then dump heat into the ice bank in the summer for better overall energy economy.  One of the first such studies I read was done by the Oak Ridge National Laboratory in the late 70s.  This is one of the papers produced.  Several large commercial buildings produce ice during night-time hours when outdoor temperatures are lower and electric rates are cheaper, in order to provide lower cost air conditioning during the day.  These systems are not passive, although there may be some that incorporate passive features.

A very simple example of domestic refrigeration was done in Essex Vermont.  I know of two such installations:  one was a refrigerated store room, and the other a freezer.  These are largely passive systems in that they do not actively pump heat, but instead freeze a large ice bank of plastic bottles with the frigid New England winter air.  Read more ›

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Posted in Refrigeration, Refrigerator

Homesteading Refrigerator to Die With –Part 2– Insulating to Decrease Load

Posted on July 6, 2018 by mcpletcher — 2 Comments

In an effort to reduce the power consumption of a stand-alone domestic refrigerator an upright freezer, I will be adding additional insulation to standard units.  A large amount of the heat gain (and thus heat to be pumped out), leaks through the walls of the cabinet.  Another great source of heat load is air leakage around the doors, so quality seals are a must.

Insulation

Insulation types have changed greatly over the years, from horse hair, charcoal, cardboard, rockwool, cork, fiberglass, to to the standard today:  urethane blown foam.  Although it could be fun and beautiful to build a cabinet from scratch, this is a project for another time.  Manufactured cabinets are so incredibly common, people pay to get rid of them, so I might as well use this as a good sealing core to my fridge and freezer, and insulate around that.  I could build a large wooden box, finish the outside with tongue and groove with trim, support the core cabinet in the center of the box, and blow in an expanding foam around it, but I’d prefer to avoid nasty (and messy!) substances like these.  Instead, mineral wool bats or thick sheets will be strategically placed over the top, bottom, back and sides.  The sides, top and bottom should extend out a few centimeters to account for the recess of the door.

Likely an ice refrigerator from the early 20th century

Door

The door itself will be insulated similarly to the cabinet, fully enclosing it with mineral wool, or perhaps a foam board.  The face of the door is finished with wood in the same style as the cabinet.  The nature of the recessed door won’t allow Read more ›

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Posted in Refrigeration, Refrigerator

Homesteading Refrigerator to Die With – Part 1 – Background and Selection

Posted on July 3, 2018 by mcpletcher — 1 Comment

This is a proposal for a refrigeration system which is intended to eliminate the need for electricity as much as possible.  What follows is my refrigerator and freezer; it is not for everyone, and it is not designed for commercial sale.  I have no such aspirations to patent or in anyway restrict the free application of my ideas.  Potentially, if a favorable method of low energy cold storage is found, I might manufacture and sell components or custom installations, but this is not the impetus for my efforts.  This is purely a work of passion and a long time desire to create refrigeration capacity outside the paradigm of fleeting cheap energy.  Society is far too complex and interconnected, with the technology that supposedly freed us from drudgery, has instead taken on a life and evolutionary path of it’s own, leaving our roll as the biologic hosts, and committing us towards a path of diminished autonomy, guaranteed collapse, and potential extinction.

I’ll be discussing methods to lower the energy consumption of standard refrigerator freezers, the use of passive seasonal ice to offset heat load, two-phase thermosiphons to conduct heat, slurry ice generation, thermal ejector refrigeration, wood fired absorption refrigeration, and perhaps a few more topics.

Background

With the exception of being applied in a slightly novel and conceivably original way, none of these ideas are truly new in the sense that they were pulled from thin air.  Quite the contrary, they come from the study of refrigeration technologies as they go back two centuries and beyond, where their application made economic sense given the resource limitations at that time.  Although I wish to build these things and demonstrate their effectiveness, I realize they will take years of experimentation and hard-won knowledge that only comes from empiricism.

I also know there are a handful of low-tech enthusiasts that would appreciate a discussion of alternatives to a store bought refrigerator, as the model of industrial manufacturing only provides temporary nutritional advantages, setting us up for a rough withdrawal when the bottom of the fossil fuel bucket is scraped clean, and a handful of people at present want to cut ties with the technosphere.  Any individual interested in these concepts is encouraged to experiment with them and contact me in regards to collaboration.  Much of what follows requires a level of expertise which I do not yet possess, but I have built enough devices along these lines that I feel the problems can be solved.  Many of the designs are kept technically simple and largely avoid controls and valves as we progress.  These I feel, can be approached by a refrigeration novice with a desire to do some research and put the time in.  There are a range of projects that get progressively more complex in the sense that the optimum operational target gets smaller and farther away, so it will only come with patience and practice.  There are a handful of concepts that generally follow a theme, mixed and matched, they form several possible scenarios  that depend on site specific characteristics and practical limitations of size and space available.

Energy consumption per unit of refrigeration (efficiency) is not necessarily the ultimate goal.  Instead, passive systems are sought wherever possible, and when active energy inputs are required, low grade sources are preferred over high exergy electricity.  Some of the initial work will in fact use electrically powered compressors, but Read more ›

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Posted in Philosophy, Refrigeration, Refrigerator

When Hell Freezes Over – Risks and Rewards of Refrigeration

Posted on March 24, 2018 by mcpletcher — Leave a comment

You’re god damn lucky. You really are. Out of all of the hominids born in the last few million years, you were born at a time of abundant energy and refrigeration. Yes, refrigeration – and on top of that, you were born into a society geographically situated and historically fortunate to be disproportionately wealthy, and actually have access to refrigeration. Most people take a technology like refrigeration for granted, not considering the profound ways in which it has altered  what you eat, when you can eat, where it comes from, and ultimately who controls the system that produced it. ‘Artificial cold’ is a blessing to be sure, but it is also a curse. To what degree does refrigeration serve you, and to what degree do you serve refrigeration?  How secure is our food system, and to what is the cost of artificial cold?

Aside from the wealthy aristocrat chilling a beverage, or having his servants concoct a frozen treat, few early 19th century North American inhabitants had any use for refrigeration – why would they be concerned over a problem they aren’t even cognizant of? People would have been getting along fine, more or less, utilizing traditional methods to grow, harvest, prepare, cook, and preserve foods. Certainly, a few individuals made use of ice harvested in winter lakes to help transport perishables to market, but generally speaking, the ice industry would require decades to mature, and to the early observers, success was not guaranteed.

A man by the name of Frederic Tudor got the hair-brained idea to ship ice, harvested in the northeast, to ports in southern latitudes.  The frozen water was to serve as ballast on a ships southern route, the ice would be sold to individuals or businesses unaccustomed to such things, and the ship would return laden with cargo destined for northeastern ports.  The enterprise was initially an abject failure, as he had no place to store the ice once arrived in port, which wasn’t the dilemma it sounds like because little to no ice would survive the trip. However, with perseverance, better insulation techniques, improved harvesting methods, and the establishment of a viable ice market, Tudor found success, even if he was constantly plagued with financial woes.

Long distance and international transport of ice would ultimately pale in size against the domestic market within the United States.  Almost every food would be affected by ice and refrigeration: dairy, beef, hog, chicken, fish, produce, and even beer. In the 20th century, refrigeration technology would change the homes we live in, where they are located, the commercial structures we do business in, and make possible all sorts of industrial processes.

Over the span of a century or so, refrigeration became an inextricable linchpin in our food system. No longer would people be limited to the produce available in their geographic region. Shipped from far and wide, stored in warehouse cold rooms, these foods were shifted temporally by making them available out of growing season, their ripening and decay artificially prolonged by the colds tempering of the bacteria on and within the skins. Grown on larger and more consolidated plots of land, where fruits and vegetables could be cultivated in more ideal conditions, then transported from afar to the market with the greatest demand, and at the greatest profit. Railroads crisscrossed the nation, and new communication systems helped to ensure a timely and efficient delivery. This bounty was now obtainable by a citizenry of new urbanites, wealthier perhaps than their forebears, packed into dense, sprawling cities, they were participants in the burgeoning market economy, and participate they did. All the while they became distanced from the source of their food, more commodity than sustenance.

The beef industry changed too. At one time, it was far less consolidated than we find today, as cattlemen had to drive their herds into the cities where they would be slaughtered for hasty consumption. Live cattle could be transported via rail, but at considerable expense, so dismemberment and curing was another practice as well. Growing cities could no longer burden themselves with the foul smells, and unsanitary detritus of slaughterhouses feeding millions of urban dwellers. Iced railcars and cold rooms would change all of this. Now ranches with thousands of cattle could be fattened on mid-west grain, butchered, chilled on ice, then shipped off to markets countrywide. Monopolistic tendencies were quick to rear themselves with beef barons joining the ranks of the fabulously wealthy and powerful.
Read more ›

Posted in Personal, Philosophy, Refrigeration, Refrigerator

It’s Evolution Stupid!

Posted on March 18, 2018 by mcpletcher — Leave a comment

The recognition of one’s own ignorance is a valuable component in the character of the individuals I care to correspond and share personal time with. In a world of “leaders” and followers, politicians and prophets, “experts” and arm-chair economic theorists, positioning yourself as ignorant won’t do much in the way of establishing credence amongst your fellow travellers on the ship of so called Progress. People are constantly looking for answers to seemingly urgent issues regarding the economy, government, and the environment, yet the questions we are able (or politely willing) to ask are so often curtailed by the base assumptions of the (increasingly homogenized) culture, and our steadfast determination that we are in control of our own lives. For all the bad blood in the world, the eons of fighting and conquest, revolts and reforms, as well as the advancements in the sciences, so few people are comfortable discussing (if even cognizant of) the role to which technology plays in almost every facet of our lives.

Our technology defines the way in which we affect the world at large, and affect each other, but this works both ways, and the encroachment upon our much prized free-will isn’t always apparent; suppose 7.6 billion of us were ignorant of the air we breathe, which by the way is being considerably altered by our technology. In fact it would be an arduous task to find a place on the surface of Earth untouched by the chain saw, the plow, the paver, the fishing trawler, or the fine particulates to heaps of plastic refuse cast upon the soil and sea.

Much debate surrounds the future of human kind and the habitability of life on Earth, with great emphasis on the all-important technology that will rescue us at our final hour.

Read more ›

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Posted in Organized Entropy Expansion, Personal, Philosophy

Technology, Autocracy, and Extinction

Posted on November 5, 2017 by mcpletcher — Leave a comment

I’ve gone through something of a trauma recently.  Nothing to get excited over, more of an existential thing, or a re-analysis of my own values and outlook on the world.  I have spent so much of the last few years thinking, researching, and studying the history of refrigeration, I nearly forgot the seriousness of the predicament humanity finds itself in today.  Civilization is doomed, and I’ve known it for years, yet somehow in the course of day to day events, I fooled myself into believing it wasn’t really so.  That’s not exactly true; in the course of conversations with people concerning world events, I would invariably shoehorn something in there about the amount of plastic in the oceans, or the depleting aquifers, or the melting methane hydrates in the arctic, or the rapid evolution of pathogens to resist anti-biotics, or the precariousness of mono-crop agriculture, GMOs, oxygen devoid dead zones in the ocean, peak oil, peak copper, peak iron, peak food, peak water, peak civili-fucking-zation- the sheer audacity of industrial civilization trying to grow endlessly on a finite planet.  But alas, these conversations rarely touch on more than two or three of these topics or others, before I was countered with a shoulder shrugged:

“Yeah, but what can you do?”.

Stand and look at the fucking spectacle, that’s what.

When the people around me are unwilling or unable to recognize the big picture- the visibly broken railway track ahead while the fires of civilization are stoked further, I found myself gravitating- no, clinging to something of real importance and impact on society at large: refrigeration.  Since moving to Portland, I became infatuated with the history, technological and aesthetic beauty of domestic refrigerators prior to the 1960s.  Immersing myself in patent literature, and later the social history of refrigeration, an overpowering drive came over me to Read more ›

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Posted in Personal, Philosophy

Fridge Powered by Farts and Rainbows

Posted on February 8, 2017 by mcpletcher — 2 Comments

The most difficult part of designing a durable, robust, long lasting refrigerator is dealing with the the question of how to power it.  Electricity is the answer most people would pop off before I get the last breath out.  But, that doesn’t really answer the question sufficiently.  Electricity from what source?- I might ask.

This may seem trivial to most people, but it really bugs me, considering the great deal of time I spend designing this machine and pondering all of the possible futures, homes, failures, and repairs it may go through.  This is nothing to be taken lightly.  Man-made, controlled electricity is not an entitlement to modern living, and it hasn’t been around very long, so the suggestion that elecctrical power could one day become scarce doesn’t strike me as anything odd.  The world has likely hit peak conventional oil production more than ten years ago, and the days of inexpensive coal and natural gas may be short lived, peaking in the next forty years or so, we’ll say.  On top of the fact that worldwide demand for energy shows little signs of declining, and when it does start to decline (and it will), then people are going to have much greater concerns in their lives than how are they going to pay the electricity bill (like where are they getting food to put in my fridge).

Efficiency improvements through technology:  Not an energy source.  Does not change the laws of thermodynamics.  Cannot replace energy with technology.

Then there’s nuclear:  Toxic.  Dangerous.  Insane

Fusion power:  60 years and still dumping money down that pit.

Again, my common friend will say that the economy will shift to sustainable sources of energy (“renewables” they call ’em) like solar, wind, and hydro.  Well first of all, I seriously doubt an expanding industrial economy can operate on these “green” forms of energy converters.  The economies of today formed around the basis of super abundant cheap energy derived from fossil fuels. Without fossil fuels to mine the raw materials and process them into the infrastructure needed to supply the needs to this wasteful culture, any notion of a solar economy is at best a pipe dream, unless we’re talking about the solar economy that life itself has operated upon for billions of years.

Rooftop solar is just a temporary band-aid, and only provides a false sense of energy independence.  This can produce electricity for home use, office, and light industrial, but the unsustainable nature of PV panels will shine light on the ugly truth.  Home-grown wind power might have a little more life, but again is very limited.  Hydroelectric power destroys rivers.  Life needs free flowing rivers.  Enough said.

I’m not holding my breath on some new breakthrough technology that will make energy so cheap that it is free.  I think that is the last thing this sick culture needs.  What we need is to look at the gluttonous monsters we are, and the way we are destroying the life support system that is our home planet.

I’m not going any deeper down this rabbit hole of doom and gloom, because I’m not the best resource for it.  If you want to read some good authors that take a realistic look at the authoritarian technic called “industrial man”, shoot me an e-mail.  This guy writes about refrigerators.

The answer, for now, is low voltage direct current.  The reason is pretty simple.  DC allows for an off-grid installation, and that is likely to be where the most interest in a refrigerator built in such a strange way, and with such strange principles instilled in it.  Focusing on this application also drives me to make it run in a way which requires the least amount of energy and considers the intermittent nature of power availability in home energy production systems.  DC inverter compressors also have the capacity to vary the capacity, leading to further energy savings and fun.

These compressors will someday cease to be manufactured, and/or the electronics which drive them will become unavailable.  The best I can do is to design a refrigerator that considers this as a possibility, and makes the conversion to another form of compressor as easy as possible so the owner can at least consider repairing the unit.  This is done my making the compressor mounting extremely adjustable so a variety of compressor mounting configurations can be accepted.  All of the copper plumbing should be easily accessible with sections designed to be cut for component replacement.  1/4″ flare Shrader valves are provided for easy access to the the system.  Integrated pressure gauges are installed providing for easier diagnoses if a problem should present itself.  All of the electrical should use standard components that will likely remain common for years to come.

I can’t be sure the refrigerator as I design it will always be applicable to the electrical sources available in the future, but I can be damned sure that I tried to give the owner as much help in making it run on whatever is available at the time, even if it is farts and rainbows.

-M.C. Pletcher

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Posted in Personal, Philosophy, Refrigeration, Refrigerator

Bringing Materialism Back

Posted on February 5, 2017 by mcpletcher — Leave a comment

It is a worthy undertaking to redefine what we know as “materialism” in today’s culture.  The word is so often associated with excess, waste, and possessing more stuff than the neighbors have.  Keeping up with the Jones, or what not.  I have recently come to the realization, as have others in the past, that the materialist tendencies of our culture is a misnomer or at the very least a misunderstanding of the term, and if we really were as materialist like some critics may argue than we should have a real appreciation for material goods, rather than just merely consuming them- to be discarded like a used napkin when they no longer appeal to our needs or wants.

Our collective consumerist nature is no doubt a concern, and is a one of many defining characteristics of a diseased culture seemingly determined to destroy the natural world from which we have taken so much.  I would argue, as have others, that a materialist culture should set a high standard for their goods and possessions, rather than settling for mass produced junk I usually view as landfill garbage sitting on a store shelf, waiting to be thrown out.  I know I’m not alone in this assessment; it is common in our cynical culture.  Planned obsolescence as a conceptual term has reached the mainstream lexicon long ago, and although so many people demand something better, for various economic reasons fundamental to the system, and marketing strategies absurdly effective in their ROI, we live in a throwaway society.  Nothing will change until the conditions of the economic system change- a change will be made for us, based on true resource scarcity, rather than artificial capitalist driven scarcity.

The values we use to evaluate goods for their usefulness is obviously decided by the culture and conditions of our lives at the time, and unfortunately on the grand scale, the consumerist trends are going to continue until the material wealth (squandered for two centuries or so) no longer can provide the standard of living so many people take for granted.  Societies rise and fall, power centers shift, and ways of life which today seem natural and concrete, will one day be viewed as antiquated and silly, or forgotten completely.

So much is lost when a society collapses, and I doubt the Facebook server farms with your vacation pictures to Costa Rica will be a high priority when folks are struggling to keep from starving.  There is no solution to these problems- no technofix.  The time for change has come and gone long ago.

Everything I say and do comes back to refrigerators, and this article will be no different.  A better refrigerator won’t save our way of life, that’s absurd.  I don’t want to save this culture; it is diseased and claims to dominate the universe and everything in it.  That’s why I have said before that the refrigerator I want to build is for no one alive today- it is for the yet unborn.  It is to be a expression of my appreciation for a technology that will cease to exist one day.  Perhaps in a few hundred years, the knowledge and technical ability to mechanically cool food stuffs will have vanished.  Perhaps it will no longer be necessary as human beings return to a way of life similar to that of successful people of the past few hundred thousand years.

In the interim, we have a surplus of human beings, and refrigeration has proven to be  useful tool in the storage of food nutrients.  In fact, artificial refrigeration allows for expanded populations- a great threat.  It is in fact one of those dangerous technologies we have become dependent on like automobiles, electricity, and agriculture.  It is quite likely that folks will need refrigerators for the remainder of my lifetime, and probably after that as well.  I’d like my refrigerators to be durable, serviceable, and beautiful enough to foster the same appreciation I have for the technology, and the values I have to be communicated well enough through its construction, that it is not only worth restoring and maintaining, but those values encourage others to pursue a better refrigerator of their own, or the creation of other durable goods for a culture (or even subculture) that cares about real materialism.

-M.C. Pletcher

 

 

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Posted in Personal, Philosophy, Refrigeration, Refrigerator

Designing a Refrigerator at 55mph

Posted on February 4, 2017 by mcpletcher — Leave a comment

I have purpose.  Purpose is good.

I’m building a refrigerator.  The question I get asked most often is, “Why don’t you just go buy a refrigerator?”.  They just don’t get it.  I understand that it is an unusual hobby, but maybe I’m just an unusual guy.  Honestly, I spend most of my waking hours pondering the construction and guiding principles of the design, and I have more trouble thinking of a reason NOT to build one.  This is by far the most satisfying work I have ever done.  Little concern is paid to the cost of tools to build my machine, as the rewards are worth several times expense.  I only wish it was summer again, when I was getting the most work done; the cold rain, wind, and short days discourage me from spending time in the shop- leaving me with a dissonance between the design in my head and the design on my bench.

The days are getting longer, and soon warmer.  In a few days I will have a TIG welder for the next phase.  Between that and the other metal working tools I have acquired recently, there will have to be a lot of experimentation and practice before I can proceed with the design as planned.  The current fridge is still built upon the same platform I made six months ago.  The next model will be completely made from scratch, and will incorporate welded stainless steel heat exchangers, a hyperboloid condenser, a better glycol evaporator (with drain and fill plugs to facilitate the change-out of solutions easily), an adjustable mounting system for the DC compressor, integrated circulating fan for the glycol tank, a finished looking control panel with gauges, and if I don’t get too excited to slap everything together, a plastic welded mating system with integrated insulation to mount everything into the refrigerator cabinet.

It is all quite a tall order, and will be very taxing on me over the next few weeks, but I am most excited to get to work.  I have solved many of the problems having to do with the general organization, serviceability, and the construction techniques required to assemble it.  The things that aren’t known have to do with the proportions and final dimensions.  I have to do some tests with stainless steel fins first to see if my theories hold up.

The strange thing is that I can keep the hole thing together in my head without drawing it, aside from one or two quick sketches to assist in a hurried explanation to the few that are polite enough to listen to me ramble out an outline of my thoughts.  A thorough explanation would take hours.  This is the first I’ve written of it in any detail at all.  Most of the real design work occurs at work while I’m driving around a delivery truck, hauling heavy equipment.  I keep a mental list of problems which need solving, and I’m sure a fly on the window of my truck would see me talking to myself as I check-mark each one solved and each one I need to put a pin in for later.

I spent some time thinking of a name for the project, but nothing has really satisfied my requirements.  One word reached the top of the list: Benchmark.  Although it is kind of clunky, as my wife reminds me, it does say a lot about my values as I go deeper into this.  No design is ever going to be perfect, and I always want to be striving for something better.  Each new model sets a higher benchmark from the last.  If this project is ever going to be a success, that is, if anyone is willing to shell out a few bucks for my machines, then it allows me to continue improving on my designs to get these things out there into the world.  I also view the word benchmark as appropriate because it could also represent a standard by which someone else views the integrity of a design.  I’m certainly not so deluded as to think I have the best ideas in the field of refrigeration, but I want it to be clear that every facet of the design is done for important reasons; they may not be novel or new, but they are value based, having nothing to do with profits.

Another word I’ve considered is “Heirloom”.  Although it sounds a bit too pretentious, like I’m trying too hard or something to make something that people would like, my hope is that I can build a machine worthy enough to keep in a family or community, rather than discarded to the rubbish heap or hocked on Craigslist for $50- you pick up.

I shouldn’t worry myself over a name, as the construction of the machine is most important, but since so much of my efforts are value driven, a name is kind of important.  As of this date it is just “Mechanized Chilling Module” or MCM.  It’s simple and descriptive, but lacks any soul.  It’s one of those things I work on when I need a break from mental construction, and will work itself out in time.

I’ve written a lot about the guiding principles of designing a decent refrigerator in the past, but I have much more to say on the subject.  Perhaps next time.

-M.C. Pletcher

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Posted in Philosophy, Refrigeration, Refrigerator

Modular Refrigerator Project Update- Part 2

Posted on February 3, 2017 by mcpletcher — Leave a comment

See Part 1

Continuing with my project update.  This is over several months of work beginning in the summer of 2016, and concluding at the present.

For a while, I ran the machine with a glycol freezing evaporator and the copper static condenser.  Operation was improving everyday as I learned the characteristics of the system and how to adjust the system charge, as well as the thermostat set points.  The condenser had obvious drawbacks with its poor subcooling, and I knew I would eventually be replacing it with something else.  Storing cooling capacity in the glycol mixture (a non-eutectic solution) has the advantage of long run times with longer off times.  This is especially useful in a capillary tube system which can take a little while to come to proper run characteristics, such as dense suction vapor and good mass flow through the compressor.  So several short cycles aren’t normally gong to be efficient as few longer cycles.  There is also great interest in making the system DC powered for a battery off-grid setup.  Longer holdover times could be useful when energy isn’t available.  The disadvantage to a system like this is that during the run cycle it must discharge all of the ehat absorbed by the glycol during the run and off cycles; several hours of heat in a fraction of time it took to collect.  I have long sought to build a phase change material based condenser.

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The cheapest PCM for the temperatures involved was white paraffin.  Pure samples could be used which have a majority hydrocarbon lengths (and melting temperatures) of a specific point, however thes Read more ›

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Posted in Refrigeration, Refrigerator

Modular Refrigerator Project Update- Part 1

Posted on February 1, 2017 by mcpletcher — Leave a comment

Long overdue for an update, I have these backlogged photos of my journey towards building a better refrigerator, and I feel I need to get these published so I can pursue further writing.

See Part 2

The last nine months or so in my shop has been productive, in my opinion, and I have turned out a great number of variations on the simple device commonly called a domestic refrigerator.  I’ve bent a lot of copper, gone through a fair amount of propane refrigerant, and done a great deal of thinking.  Although seeing an idea come to life fills me with much satisfaction, it is dreaming up the next big idea which gives me the most excitement.  You’ll see that I have gone through an absurd number of iterations and that each one followed a line of thinking which sought to test and evaluate each for its suitability in the pursuit of worthy technology for a rugged, reliable, and efficient refrigerator which could serve domestic purposes for generations.  I’ll start where I left off in Beginning the Modular Refrigerator.

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From this photo, you can see there was some thought put into the organization and layout of an experimental modular unit.  Ultimately, this system would be plagued with capillary tube problems, as I hadn’t yet determined the Read more ›

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Posted in Refrigeration, Refrigerator

A Refrigeration Laboratory

Posted on January 7, 2017 by mcpletcher — 1 Comment

The refrigeration laboratory is here.  This is the first blog post I’ve written since late summer 2016, and I’m doing so on a desk and chair I purchased at the Goodwill Bins for $8, not more than an hour ago.  It’s funny how much the environment can change one’s behavior so.  Before the weather began to turn cold I was cranking out at least two YouTube videos per week on the progress of my 100 Year Fridge project.  I told myself that video was the only good way to document my work, because I just didn’t have the time to write and caption pictures.  It is true that I was insanely busy bending copper, soldering stainless steel, concocting new heat exchangers and two phase thermosiphons, so sitting down to carefully explain what I was doing would take at least as much time as I spent building the shit (which was a lot).  But I realize just now that part of the problem with writing is just getting started, and it sure is hard to start when there are so many distractions to prevent that.

I sit in an 8×10 foot windowless shed, well insulated, and accompanied little more than a homemade beer fridge, a heater, and the laptop I’m writing this on.  Read more ›

Posted in The Squatch

Designed For The Unborn

Posted on August 18, 2016 by mcpletcher — 1 Comment

Let it be known that I do not want to sell refrigerators, own patents, market products, or operate anything which could be construed as a business.  That being said, a guy has to make a living, so that if I were to develop a domestic refrigerator I feel confident in, then I would probably attempt to sell them, constructing them by hand, one by one.  However, if the world worked differently, I would spend my days building refrigerator after refrigerator, making refinements both in utility and aesthetic appeal.  For now, that is exactly what I am going to do, while working a regular day job.  Perhaps I will never feel that I have a machine good enough for sale, and I will tinker away in my shop for the rest of life trying to make the perfect refrigerator.  This is all speculation, but I really feel like I do work on this for a very long time.

Improvements in technology over time, when driven by competition though the market process, seem to produce individual machines of increasing sophistication and individual energy efficiency, but shorter useful lifespans. This, I feel is due to a mixture of cheap components “made to break”, and a lack of sensible repair options, Read more ›

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Posted in Personal, Philosophy, Refrigeration, Refrigerator

Beginning the Modular Refrigerator

Posted on July 10, 2016 by mcpletcher — 4 Comments

Beginning a few weeks ago, I’ve embarked on a project to construct a modular, long lasting cooling system for  domestic purposes.  I’ve outlined my reasoning for this elsewhere on this site.  100 Year Fridge  The majority of my documentation is on YouTube at this time, so I thought it prudent to begin sharing some of the details of the design in a less “rambling crazy person” format.

The first cooling unit was not an all-in-one package, and much more crude, so I won’t be including much of it here.  The unit I built was essentially a smaller brine chiller.  That is, it was designed to chill an insulated container full of anti-freeze and water.  Initial tests were a partial success, as I was able to lower the temperature far below freezing, but not in anything resembling efficiency or longevity.  The system was comprised of a 1/4 HP compressor salvaged from an ice machine, a small air cooled condenser, a short length of capillary tube, and a short length of 1/4” copper tubing immersed in the brine tank.

Construction was for two purposes.  Initially, I wanted a brine chiller so I could test simple two-phase thermosiphon.  I won’t go into it now, but the thing worked just fine, and demonstrated the principle could be used to refrigerate remote liquids (and possibly air) from a distance.  The original refrigerative apparatus was consolidated to a single platform with the condenser unit mounted to the surface of a board, and the evaporator suspended from underneath.

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After this proof of concept, I returned to the long term goal of making a successful cooling unit for a refrigerator.  A mini-fridge, originally thermoelectric, was re-purposed by cutting a round hole in the top, Read more ›

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Posted in Refrigeration, Refrigerator, The Squatch

A Refrigerator For The Ages

Posted on July 5, 2016 by mcpletcher — 2 Comments

Over the course of the next several years I will be illustrating a plan for a long lasting, modular refrigeration system which encompasses my values in the realm of design and simplicity.  Here I will begin that process by trying to describe these values in a somewhat coherent manner.  Writing, or even conversing openly about this project is very difficult, as putting these concepts to words in an easy to understand format is fraught with many mental blocks.  Providing the necessary background information to understand the needs of a new direction in refrigeration engineering seems to be my greatest shortfall.

From my perspective, the well crafted machines of the 1920’s and 30’s represent a beauty and simplicity which remains unmatched to this day, in my opinion.  I have a nostalgia for appliances from my grandmother’s youth.  This is strange to some, considering my age, but I am not alone as there are many collectors of vintage refrigerators, as well as restoration experts, and clueless yuppies willing to fork over a pile of cash for an old looking fridge with modern cooling equipment.

Where I feel I may differ from many of the others, is that I want to bring back some of these technologies which were developed at that time.  Engineering problem solving produced modular cooling units that were separate from the ice box and could be swapped when a problem occurs, also detailed service manuals were produced to make repairs.  Refrigerants of the day (other than the Freons) were often inexpensive, naturally occurring, or produced by simple chemical synthesis.  Many of the most successful insulating materials were again naturally occurring, or produced from a simple industrial process.  When implemented well, they were resistant to rot and vermin attack.  The structural components of the compressor unit and ice box were common materials like wood, felt, cork, mineral wool, glass, and metal.  Time has shown that many of these models were handsome, sturdy, reliable, and long lasting.  In retrospect, the scientific community has shown the ecological dangers of the Freon group, adverse health affects of asbestos, lead paint, and mercury.  But, they were all good ideas at the time, I guess! Read more ›

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Posted in Personal, Philosophy, Refrigeration, Refrigerator

Design With Planned Integrity

Posted on July 4, 2016 by mcpletcher — 2 Comments

It has taken me some years to find my path.  I believe that were I born in a previous era, I would have found my way to the field of engineering, as that seems to be the my core interest:  solving problems and building better things.  Alas, this was not the case, and I was born into sick world from the toxic effects of over consumption and growth.  The principle of problem solving is no longer the goal of the average engineer beyond the band-aids slapped onto the bad designs inherited from the last iteration of uber-complex, mass produced garbage.

Having just entered my third decade of life, the aggregate experiences of working many jobs, social experiences, and a decent body of literature, has left me with the humbling realization that although I do not have a solution to the world’s problems, I nonetheless recognize their existence and severity.  My greatest criticism of our technological culture lies in the things we make, their social and environmental consequences, and the obsessive, bordering religious, quest for “progress” which has been described by others as a “cult of efficiency”.

I am one man, with a variety of basic skills, writing well not being one of them, but I have learned and applied these skills in several vocations that typically involve the maintenance of industrial machines and furtherance of the systems underlying industrial society.  Each one of these positions came with it a new perspective of engineering, design, the bureaucracy of management, and dynamics of the economic and political system which governs it: neo-liberalism.

Listing back and forth between cynicism of human nature, Read more ›

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Beware of HVAC Technicians

Posted on June 26, 2016 by mcpletcher — 6 Comments

In the fall of 2015, I did something which I felt was for my own good:  I quit my job as a local truck driver, and pursued a residential HVAC maintenance position at a Portland area company.  My view then, for which I still stand by, was that the sensible thing to do was to work in a field or related field that could teach me a valuable skill, and for the first time provide an opportunity to really use my head, rather than only my back.  I have long considered HVAC as a trade, but was too cautious to throw my hat in the ring, since the vast majority of the fellas I’ve met doing HVAC or refrigeration were ego driven, pig-headed, stubborn assholes with a god complex.  Also, by its very nature, HVAC techs works a lot when it is really hot or cold, and not always in the most favorable of environments generally.  I want to be in this to hone my brazing skills, get plenty of trouble shooting experience, and hopefully make a little money to fund my personal refrigeration projects.

In nine months or so at this company, I went from curiosity and excitement, to boredom and cynicism.  That part is hardly new; I always get bored.  The strange part came from an initial image of ongoing education, and good honest work.

Starting in installations, I was impressed to see the quality which the journeymen strove to achieve.  This work could be pretty labor intensive, especially if anything needs run through the attic or crawl space.  I’m not as nimble and flexible as I once was.  Leave that labor to the younger guys.  I was moved to the maintenance program within 6 weeks.  After all, I was hired to eventually do repairs.  On this side of things, I saw that good old god complex attitude in more than one technician, but there were two good technicians for every one bad, so I can live with that.  The part that bugs me, is the amount of sales we are expected to achieve.

I’ll try to lay out the general scheme here.  This program is practiced around the country (US) in various forms, but this is how mine worked.  Read more ›

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Who’d Build a Refrigerator?

Posted on October 6, 2015 by mcpletcher — 4 Comments

In the previous post, I proposed some design principles for the construction of a better refrigerator, and suggested that an “open source design” model could be used to improve it continually through collaborative effort, and an iterative process.

Being that this is a physical machine, requiring raw resources, energy, specialized tools, and physical labor-  to be produced, it will not likely be done for free.  That is, although the design should be completely open, anyone is free to build and sell one without ethical dilemma.  A growing segment of the population is becoming keenly aware that industrial humans have a detrimental impact on the planet, and that one way in which to stem problem, is through the everyday choices we make.  There seems to be a lack of choice when it comes to a domestic refrigerator.

Potential

  • The environmentally conscious
  • Minimalists and tiny house dwellers
  • Off grid dwellers
  • Collectors of hand made goods
  • Tinkerers, hackers, DIY community
  • Educators

 

I would very much like to build a complete refrigerator from scratch, and I may very well get to do that one day, but for now, I’m trying to picture other forms this machine may take, and develop some versatility such that unpredicted possibilities may develop by others.

The Various Forms Which The Refrigerator May Take

Read more ›

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