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Thread: Daikin ASHP: Optimising Setting
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28-02-2012, 06:38 PM #1
Daikin ASHP: Optimising Setting
Hi All, I have recently moved into a new house with a Daikin heat pump, its all working well but my electricity bill is very high approx £250 per month (I have a smart meter).
I had the installer come in and check a few things and we found some incorrectly set thermostats which have been corrected. I have also switched off the additional hot water circulation system that was installed as this just seems to rob the tank of hot water and cause the pump or booster to constantly cycle. Currently I have also switched off the booster heater as it seems keen to switch on for about 15 minutes each hour.
While the installer was here he said that they normally set heat pumps to run all the time topping up heating and hot water when required. However looking at my smart meter it seems to be doing a fair bit of water heating during the night and I don't think this is needed.
I am tempted to switch the water heating function off from about 2200-0500 but Is this sensible ? is it possible to control when the booster heating is used?
There must be a balance between heating the water with the pump and heating it with the boosters but I am not sure how to set this or what the relevant parameters are.
I have a feeling that getting a heat pump equipped house set up for efficient energy use is a little more complex that I thought it would be.
In case anyone can offer some suggestion for optimising my setting here are a few details:
- House is a large detached highly insulated timber frame building with 5 bedrooms but with only 2 people living in it.
- Most of the living room stats are set to 20 or 21.
- Most of the bedrooms and other rooms are set to 17 or 18 or lower.
- We have a heat recovery system.
- Heat pump outdoor unit is a Daikin ERHQ016BAV3
- Heat pump indoor unit is a Daikin EKHBH016BB6V3
- Tank is a Daikin EKHW5U300B3V3
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28-02-2012, 08:48 PM #2
Re: Daikin ASHP: Optimising Setting
How does this compare with the energy usage forecasts? I'm assuming that this is a Low Temp system?
I had the installer come in and check a few things and we found some incorrectly set thermostats which have been corrected. I have also switched off the additional hot water circulation system that was installed as this just seems to rob the tank of hot water and cause the pump or booster to constantly cycle. Currently I have also switched off the booster heater as it seems keen to switch on for about 15 minutes each hour.
While the installer was here he said that they normally set heat pumps to run all the time topping up heating and hot water when required. However looking at my smart meter it seems to be doing a fair bit of water heating during the night and I don't think this is needed.
There are settings available within the software that can be set to control the use of the Booster heater and the differential for when the cylinder is heated, as well as when the cylinder is heated.
I am tempted to switch the water heating function off from about 2200-0500 but Is this sensible ? is it possible to control when the booster heating is used?
There must be a balance between heating the water with the pump and heating it with the boosters but I am not sure how to set this or what the relevant parameters are.
I have a feeling that getting a heat pump equipped house set up for efficient energy use is a little more complex that I thought it would be.
In case anyone can offer some suggestion for optimising my setting here are a few details:
- House is a large detached highly insulated timber frame building with 5 bedrooms but with only 2 people living in it.
- Most of the living room stats are set to 20 or 21.
- Most of the bedrooms and other rooms are set to 17 or 18 or lower.
- We have a heat recovery system.
- Heat pump outdoor unit is a Daikin ERHQ016BAV3
- Heat pump indoor unit is a Daikin EKHBH016BB6V3
- Tank is a Daikin EKHW5U300B3V3
I have spent a good deal of time these last 3 months trouble shooting poorly designed and installed systems though.
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28-02-2012, 10:54 PM #3
Re: Daikin ASHP: Optimising Setting
Hi Frank thanks for the info.
Yes its a LT system, we didnt have any expectations of price but at the moment it does seem to be a bit high, I think this because the system is trying to keep the hot water tank hot all the time and I am not sure that this is nescessary.
OK thanks thats pretty much what I thought it was doing, I have switched it off at the moment as we don't use much hot water and I would rather keep it hot in the tank untill we need it, and accept that it will take a while to reach the taps.
Yes we do have UFH and its working brilliantly wth good control. I am pretty sure its the hot water that is the problem.
Ok I have the commissioning sheets and there are a number of set points mentioned, Space Heating is set to 43 and DHW to 48.
Understood, and I am happy that the system cope with heating the house easily it aslo produces plenty of hot water but I would like to optimise the DHW, a bit for example by turning it off at night. I woudl like to understand how the heat pump decided how to heat water? mine seems to use the booster even though the set point is lower that the pump max, I wonder if it trys to work out how well it can heat from the pump and then decides?
I think our design is sound (it also has solar thermal although thats not contributing much at the moment) I am really interested in optimising its performance taking into account our requirements. I think its been setup for a average user with some assumptions that may not be best for us.