I finished the heatpump build, pressure tested with CO2, vacuumed it & filled it with propane, then turned on the heatpump for the first time yesterday!
I charged it with the pump on, aiming for pressures I'd found with Coolselector2, which used maybe 200g of propane to give ~ pressures of 5bar(low)/13bar(high). Sadly I wrote the "before" gas can weight down on the can, which got all frosty and the number rubbed off.... and I can't remember it. The can originally had 360g in, I wasted a load last week hamfistedly putting the regulator on, and there's still some left hence ~200g. It was supplied in the "on" state, and like the CO2 one I have, I thought I had to tighten it on to stop leaks - but no, that just made it worse.. Uhh, amateur! I am doing all this outside with gloves and safety glasses on at least.
There's a picture attached - all the heatpump parts are on the outdoor grade ply, the compressor next to it is used as a vac pump. I've attached hoses to circulate water for now.
I ran it with a 3 thermocouple logger and an elec power meter manually read, with "cold" water from the tap at 8lpm being chilled down by a heatexchanger and dumped in the garden. The hot loop ran from a 27.4litre tank of water, pumped at ~8lpm through the "hot" heatexchanger, and back into the tank. I pushed the data through excel and I get some graphs, attached too. I got excel to do a linear fit on elec power in and delta(output temp), rather than use the actual data to calculate the COP, just so it's a noise free result, which I think is fine.
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