DIY freezer/cooler unit.

[Adron]

Has anyone built their own homestead type walk-in freezer/cooler unit. How did it turn out? materials etc?

I have aquired a new freezer unit. In its own weatherproof box somewhat similar to a window air conditioner. This was meant to keep about 200 cu/ft at -5º. I thought I might build a small walk-in or a freezer with large doors and baskets. Can you add a cooler as part of the freezer by thermostatically(sp?) robbing cold/cool air from the freezer?

Current freezers always has what I need on the bottom. Plus I'm thinking it could replace 2 older 15 cu/ft freezers more effeciently?

Thoughts, suggestions, recommendations and experiences are all appreciated.

[Pat]

Adron, The cuft rating of a compressor unit for a freezer is predicated on some assumptions regarding surface areas, R-Values, infiltration (air leakage), etc. If you are willing to do what is required to SUPER INSULATE and seal the assy then you can handle a larger volume, carefully done, a significantly larger volume.

Another important consideration is freezing things not just keeping them frozen. Lets say for a thought experiment we had no air leakage and infinite (perfect) insulation. Once the contents were brought down to your desired storage temperature the unit would never run again until you added some "warm" items. This is where a larger compressor does a better job. A large quantity of "warm" stuff placed in the freezer makes a large demand on the compressor system.

Super insulalting your walk-in will reduce the compressors long term workload but will not reduce the work of chilling a load of warm items. You need to be careful how much warm stuff you put in at a time. One strategy is to use the frige to pre-cool larger quantities of warm stuff so as to not put all that heat into the freezer all at once. You can warm up (sometimes thaw) adjacent things in the freezer when adding too much warm stuff.

So, the qualified answer is yes, you can increase the volume of the freezer by using more and better insulation and not strain the compressor or increase your electric bill...B...U...T... you have to resist the temptation to add a lage quantity of warm stuff which is tempting since you have such a large volume available.

A chest type freezer is more efficient than upright. A walk-in NEEDS a protected entry to be energy efficient. Either consider an airlock (double door system with anteroom) or the hanging partition of sections of plastic (flexible at low temps) or both.

With a walk-in you have to avoid the temptation of leaving the door open because you KNOW you will grab what you want and be right out. That fails more than it succeeds. Ever been to a commercial freezer space rental outfit. Some of them have loaner parkas for the customers. Keep a warm jacket handy for wearing into the walk-in AND close the door. Another good move is to put the interior light on a timer so you don't forget and leave it on. Motion detector lights are a nice idea but they frost up and quit even if the elctronics can be adjusted properly at your temp.

Another consideration when building a large freezer for a family is rotation of stock. The larger the freezer the longer on average you'll store stuff before using. Even in a deep freeze not everything lasts forever. Deterioration is slowed not stopped.

Freezers like pantries tend to be filled to max capacity regardless the size. The larger the storage volume the older on average the food you eat will be. I know it is a very simple management challenge and I know what happens in reality.

By "COOLER" I assume you mean refrigerator temps in a separate box. Yes you can. Most modern combination refrigerator-freezers are freezers with a fan to circulate cold air into the refrigerator side. Very few have a separate compressor for each function. There are several approaches but for efficiency you need the cooler co-located with the freezer and a means of controling the circulation between the freezer and cooler. Simple sliding valves (like a blast gate) are simple and effective. A small low power low volume thermostatically controlled fan for circulating the air between the freezer and cooler is needed. Canabalizing from old units might be the simplest way to get these parts.

I suppose with a little thought you could mount the cooler lower than the highest part of the freezer and depend on convection instead of a fan for air circulation. The "BLAST GATE" type flow control valve would have to be thermostatically controlled. There are electrically operated dampers for zone controlled heat and air installations that could do the job for you. Just thermostatically controlling the fan is simpler.

Good luck with the project,

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]