There's a beginners guide here
wynn (04-Mar-10)
Thanks so much. This opens up a whole new world.
In search of South African Technology Nuggets(R), for sale & trading in South East Asia.
"Nobody who has succeeded has not failed along the way"
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Thanks wynn. Much obliged.
In search of South African Technology Nuggets(R), for sale & trading in South East Asia.
Well I was inspired by this thread nearly six months ago and decided that if I was ever going to cut my electricity consumption by the 60% goal which I set myself then I was going to have to convert my HWC to a solar/electrical hybrid.
The great news is I've finally done it...reduced my consumption by 60% that is. Only thing was that what started out as a solar/electric hybrid geyser project actually ended up as a home made heat pump/electrical hybrid.
The solar conversion gave me plenty of problems (I won't bore you with the details) but the actual amount of heat input from solar was very disappointing, mostly due to Cape Town climate. Eventually I binned the solar system and tried a home built heat pump retrofit instead using begged and borrowed refrigeration components and a home made copper heat exchanger. I finished the installation three weeks ago and have now finished sorting out a few teething problems. It's early days but so far I haven't had a cold shower. There's still a minor snag with high head pressure tripping but it's working fine as our only hot water source.
For the first time at the beginning of this month I now fall under the low consumption bracket with my electrical consumption and I even got free units when I bought my batch of electric units this morning. If I now include my free monthly units that means I have actually reduced my electric costs from what would be R1440.00 per month to around R600.00 per month. Not bad for a family of four.
I promised myself a new TV when I achieved the goal so I'm out shopping tomorrow morning.
Last edited by AndyD; 03-Sep-10 at 08:39 PM.
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Jolly good show.
Watch out for the high-pressure side of things. I suspect that you'll run through a few compressors, if you aren't careful. Please also take extra care that you don't burst a condenser tube at the top end of the heating run. You'll likely blow your geyser to smithereens.
When you're in the market for a really nice, high-efficiency, ultra-safe heat-pump, give me a call. I'm busy getting all my supply ducks in a line in terms of my new product line-up for SA. I'd expect a 80-90% reduction on your water-heating costs.
Last edited by desA; 03-Sep-10 at 10:58 PM.
In search of South African Technology Nuggets(R), for sale & trading in South East Asia.
AndyD (04-Sep-10)
The refrigeration side is a little tricky, especially not being a fridge engineer. That said I'm learning by the day.
The high side tripping usually happens with water teperature approaching 50 degrees C or over. I'm a little worried because the ambient attic temp is fairly low at the moment, I think the tripping may become more coimmon with higher summer attic temperatures.
I've now installed an auto reset HP switch, the manual reset was an annoyance. I've also ended up with a fairly complex three thermostat arrangement so the heating 48 degrees and over (up to 55degrees final temp) is done only by the electrical element. 30-48 degrees is heat pump only. If the temp drops below 30 degrees then both systems kick in. I'm probably going to replace the analogue thermostats with a PID controller which can look at the temperature change trends of the water. I'm hoping that a PID control will improve efficiency as well, I must just source a suitable offering. Finally the largest expense so far was replacing the standard fan unit with a much higher efficiency EBM unit which is also considerable quieter.
Touch wood...so far no compressor failures. I have been keeping a close eye on the superheat figures and playing it on the cautious side.
If I ever need one I'll contact you but I'm going to percivere with my home made galoppie for now.
At the moment I've only been data logging the power consumption for a week but it's reduced the hot water power consumption by around 52%. Even with my planned improvements I'll I doubt I'll get close to 80%, I'm optimistically aiming for 60% savings in electricity consumption. If I factor in my free monthly units which I'm now qualifying for then I can make that figure a little higher.......but that would be cheating me thinks.
Last edited by AndyD; 04-Sep-10 at 11:41 AM.
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What is your refrigerant?
In search of South African Technology Nuggets(R), for sale & trading in South East Asia.
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