Heat Pump Hot Water Plumbed
Yesterday I finished plumbing the hot water heaters for the butcher shop. There are actually three. One of them is a highly efficient electric heat pump that takes heat out of the air and puts it into the water delivering cold air to the cutting room.
The heat pump serves several purposes:
- Heating the hot water from 45°F to 140°F slowly but with a large 80 gallon tank;
- Cooling the air for the meat cutting room which is already naturally pretty cool (currently 38°F prior to the heat pump doing anything) due to the high thermal mass of the butcher shop;
- Drying the air for the meat cutting room to minimize condensation;
- Filtering the air coming into the cutting room so it is clean; and
- Pressurizing the cutting room so it is the source of air, the start of the air cycle, to keep it more sanitary.
This uses very little electricity in heat pump mode but works slowly. The efficiency was a big sales point for me. It also has an auxiliary resistive element electric heater for when needed. Because of our work cycle of cutting meat and making sausage once or twice a week I expect the heat pump portion to do most or all of the work and the heating element to be rarely used. Still, I like having it there, just incase, which is a big part of why I bought this model. Another reason I got this one is the high capacity at 80 gallons of storage and thick insulation. It was the best I could find in our price range without jumping into the over $10K units. German engineering built in Connecticut.
The second hot water heater is an on-demand electric hot water heater that boosts the 140°F hot water from the heat pump hot water heater up to the regulatory required sanitization temperature of 180°F. That’s scalding hot. Actually, the heater takes it to 185°F to give us a little margin for loss in the insulated pipes since that 180°F is required to be the measured temperature at the end of the hose. We have a special high temperature hose, faucet and sprayer to deal with these unusual temperatures. Don’t try that at home.
This second hot water heater is 240 volts and uses a total of 132 Amps of electrical power on four breakers! Yes, that is our biggest power draw by far. It puts us uncomfortably close to the 160 Amps of our power service which is rated at a nominal 200 Amp but realistically 80% of that for continuous draw. Fortunately, when we need those scalding hot temperatures nothing else is running except low power loads like our LED lighting, the energy efficient booster exhaust fan and such.
Electricity is often an expensive way to heat water, depending on how propane is fluctuating against electric prices. My preference would be nuclear but we’re not zoned for that and I’m having trouble sourcing the uranium. I’m planning to later add solar which can get up to these temperatures with out having to deal with the NRC.
Wait, you say, “What about the third hot water heater?” Yes, well, I did say three, didn’t I… The third hot water heater is a very nice propane based on-demand system but it won’t be installed yet, maybe not for years. I’m a bit irked on that score because I spent $7,000 to install an in-ground 1,000 gallon propane tank also known as “The Bomb”, hook it up and buy a $2,500 on-demand propane fired hot water heater that I can’t use because the propane company, after two years of promising and many phone calls and letters from me has still not hooked it up. Because of their failure to hook up the propane I had to buy the electric on-demand hot water heater to replace the very nice propane one. Last week the company, Suburban Propane, had the gall to send me a letter complaining that I had not bought propane recently to fill the tank. I’ve been trying to get them to finish the install for a long time. I wanted them to fill the tank last year. So last week I called them up and went over this issue, one more time, with their customer service. They said they would send someone out, again, at some point to look it over and finish the hookup. Their guys keep coming out but without the proper parts and then promise to return “soon” and finish the job. Hasn’t happened yet. In the mean time I’ve worked around their delays and we’ll be opening the butcher shop soon with on-demand electric rather than propane based hot water. Meanwhile, no, I’m not filling the tank.
Such is life. We move onward.
Outdoors: 79°F/59°F Sunny
Tiny Cottage: 66°F/62°F
Daily Spark: A democracy is two wolves and a lamb voting on what to have for lunch. Earliest known source is Gary Strand, Usenet group sci.environment, 23 April 1990 and apparently not Benjamin Franklin, 1759 as widely attributed.