Heat Pump vs Solar Geyser

Arthur said:
Most people have fridges that can freeze to well below zero C. That is only possible if the "carnot engine" is able to extract heat from the freezer compartment to keep it below zero. A reasonable heatpump, especially if it has a variable speed compressor (using an inverter) will still make piping hot water when the air is minus 5 deg C, just take a little longer.
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The only time that a heatpump loses some efficiency (CoP) is if there is high humidity, and then it just works a little longer, but it's still far more efficient that a heating element.
 
For those with heatpumps: what was the target temperature of your heatpump set to?
And does it easily reach that temperature in summer & winter?
 
ebendl said:
For those with heatpumps: what was the target temperature of your heatpump set to?
And does it easily reach that temperature in summer & winter?
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Target temp on mine is 75 deg C. I have never had an issue hitting that target in winter. Heat pumps eat up summer for breakfast.
 
dj2381 said:
Does anyone on here use a heat pump to warm their geyser, and how well does it work vs solar geyser? I could eventually run a heat pump off solar once I go that route, any opinions or advice please.
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i had one installed, our electricity went from R1300 a month to around R700, its made a huge difference
 
ebendl said:
For those with heatpumps: what was the target temperature of your heatpump set to?
And does it easily reach that temperature in summer & winter?
Click to expand...
65 degree's

runs 3 times a day , from 4am-7am , 11-13 , and 16-21
 
Mine runs to 57 degrees in Summer, 65 in Winter (more standing losses). Also set it to do 75 degrees once per week to kill bacterias.
 
I have the ITS 4.7kW (heat) unit that draws 1.3kW from the grid for nearly 9 years now. Very happy and if I had to choose a system again it will be a ITS. At the time ITS was the only make with a loading valve to prevent mixing cold incoming water with the hot water in the geyser. My installer decided to install one of the largest local geyser manufacturers heat pump against my wish. A total disaster and 2 days later he removed it. This was due to luke warm water due to mixing of cold and hot water. Google for ITS loading valve for a explanation of it's function. The ITS unit has inverter drive so it never uses more than 1.3kW. It takes like 3 min to ramp up during starting. Start power is about 500W. Great for running shoert periods from inverter.

As per a previous comment I also had the feed pump replaced after 7 years. It also had no strainer. Cost was R1250 fitted and a small price to pay for heating water at half the cost of using an element.

Yes in very cold nights it does use about the same elec as an element but that is only on about 15 days a year. The other more than 10 months one pays less for the hot water. During these very cold nights it might take double the time to heat. Easy to just adjust a timer for longer cycles. This is purely due to the higher increase in temp needed to get to 60 degrees.

I have a lot of stats where I measured the actual power used vs the increase in temp as indicated by the controller. An element would use about 175W per degree increase on a 150L geyser. The heat pump would for 10 months of the year use less than 75W per degree.

Maintenance is seen as high. I only had my unit serviced after a year and after seeing what is done I opted to do a cleaning myself every year. I found no leaves etc in the unit. Only normal dust and also keep my PCBoard clean.

Just this morning I took another measurement and it took only 1083Wh to heat up 150L from 35 to 47 in a 50min period.

Recently I got a quote for R3500 to fit a heat pump to another geyser from a plumber if I had to fit the unit against a wall and the plumber did the 2 x T-pieces in the hot and cold water pipes. It should not be too expensive to fit to any existing geyser.

I run mine 15h00 to 17h00 and again 04h00 to 05h20 and it works for the 2 of us. If the controller shows a too low reading I just switch it on at the controller.

As we need some heating after 22h00 when we have a bath before going to bed in summer a normal solar geyser will not work for us. After running a bath our 150L goes down to 28-30 degrees.
 
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RonSwanson said:
Mine runs to 57 degrees in Summer, 65 in Winter (more standing losses). Also set it to do 75 degrees once per week to kill bacterias.
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I believe you only need to set above 55 to kill Legionnaires.
 
SauRoNZA said:
Seems very expensive.

Then rather do this and go full on day/night with minimal power usage and can run off solar too.

www.energie.pt

Ecotop

GENERAL INFORMATION VERSIONS / MODELS NOMENCLATURE HOW IT WORKS CONTROL HEAT IS CAPTURED UNDER THE FORM OF SOLAR RADITION, ENVIRONMENTAL TEMPERATURE,...
www.energie.pt www.energie.pt

Mine is being installed sometime in December/January and is about R40k and will be 7.

Your heat pump setup actually doesn't seem all that economical compared to my normal geyser usage with a timer which did 203.93kw for November with 4 people on a 250L.

Mind sending the link? I had a look at their website but couldn't find it easily enough. It seems like 99% the same thing just without the thermodynamic panel on the roof.
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Who are the local installers in Gauteng and cost? Life span? Heatpumps seem to be 10 years before requiring replacement.
 
Arthur said:
Talking about installation location, my heatpump is installed above the ceiling in the roof, above the main bedroom's bathroom, for shortest water route to most frequently used taps. There's fortunately plenty of standing room space.

The heatpump's low hum isn't really a problem. It"s set to be off from 22h30 to 06h30.

One of the best things I've ever done in house mods is having a dropdown trapdoor ladder installed. I used to hate having to get into the ceiling. A trapdoor ladder makes it so easy I almost look forward to it
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Cost to install trapdoor ladder? Might consider it for medium term.
 
Saba'a said:
Who are the local installers in Gauteng and cost? Life span? Heatpumps seem to be 10 years before requiring replacement.
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Greensun I believe operate everywhere.

Was in the region of R40k.

Warranty info is at that link.
 
If I were not heating my geyser up from the PV panels, most days, I'd seriously consider a heat pump.

This week, I think the geyser has used less than 5kWh from grid.
 
ekkekan said:
Just this morning I took another measurement and it took only 1083Wh to heat up 150L from 35 to 47 in a 50min period.
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I guess that you mean 1083Wh? It takes me 3 months to use 1083kWh.
 
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