Air to Water Heat Pump

fclauson

exaisle wrote: »

Did you do this via a timer on the HP circuit or is there a setting in the HP itself? I have a night rate meter but I haven't tweaked the HP system at all....yet!

On the Danfoss unit its all on within the HP controls

exaisle

Thanks....on my (Thermia Atria) unit, there's a section called "EVU and Tariff Control" in the installation manual. The timer is optional but hardly likely to break the bank.....

blast06

dfader wrote: »

Blast,
Thanks for this info - its very useful to those planning similar builds. I know you said your house is A2 and so this question might be somewhat academic and I don't wish to derail the tread, but since ye brought up the topic of thermal mass in the floor, I am curious as to what is your external wall build up exactly?

No problem.
Bear in mind now that i am just of an A2 by the skin of my teeth. Big difference between that and being just shy of an A1 (albeit i think the KwH usage per square metre figure in the BER report i have is miles miles higher than what i will actually use based on current usage rates).

Anyway, walls are fairly straightforward ..... normal block on outside, 150mm pumped cavity and Quinn lite blocks on inside. I also included the Quinn lites on the first row of internal walls to reduce thermal bridging. I thought after the walls were built that i should have gone for a 200mm cavity but now i'm not so sure based on comfort levels to date and given the extra challenge (and thus cost) of closing the cavity under windows for a 200mm gap plus i guess dearer wall ties. Note also, if you go with Quinn lite, you'd need to be very particular on who you get to plaster it. If you have a contractor then ensure you get feedback/examples on where the plasterer has plastered Quinn lites before.

dfader

blast06 wrote: »

OK, i've made the switch .... heating and hot water now only running between 11pm and 7am. If i can get away with this on an ongoing basis then my running costs would be almost ridiculously small ..... below would be the figures for the last 7 days if all electricity was from 11pm to 7am



Date Heating Units kWh Hot Water Units kWh Heating cost Hot Water cost Total Cost
2013-10-31 13.25 0 1.11 0.00 1.05
2013-11-01 13.25 3.5 1.11 0.29 1.34
2013-11-02 13.25 3.5 1.11 0.29 1.34
2013-11-03 15.9 0 1.34 0.00 1.26
2013-11-04 15.9 7 1.34 0.59 1.85
2013-11-05 15.9 0 1.34 0.00 1.26
2013-11-06 5.3 7 0.45 0.59 1.01

Blast,
Thanks again. Would be good to hear back from you again with this info after a cold snap. ie. sub zero external air temperatures.

fclauson

dfader wrote: »

Blast,
Thanks again. Would be good to hear back from you again with this info after a cold snap. ie. sub zero external air temperatures.

I'll also try to provide numbers - but interested in your findings

Mixupat

Is airtightness and MHRV key to the success of running a heat pump? Will it perform much worse without airtightness and electric bills shot up.

fclauson

Any heating systems performance is based on insulation and air tightness regardless of heating type

blast06

My latest figures as below.
A few comments ....

• i didn't persist with leaving the heating on during night time hours only. Wasn't brave enough - i just left it running during night hours on nov 6th
• I was messing with the heat curve on both the 9th and 22nd where i increased it from 29 to 33 for a 24 hour period just to see the impact. The one on the 22nd also coincided with the coldest of the cold spell.... probably added about 50c to €1 on 22nd
• And to recap ..... it is a 2600 sq ft house (9' ceilings) that just about scraped an A2 with a Danfoss AQ-11Kw air to water heat pump.... located in the midlands at a highish (for midlands) 115m ASL elevation

Heating Reading Hot Water Reading Heating Units kWh Hot Water Units kWh Heating cost Hot Water cost Total Cost
2013-10-30 152 63
2013-10-31 157 63 13.25 0 1.58 0.00 1.58
2013-11-01 162 64 13.25 3.5 1.58 0.29 1.87
2013-11-02 167 65 13.25 3.5 1.58 0.29 1.87
2013-11-03 173 65 15.9 0 1.89 0.00 1.89
2013-11-04 179 67 15.9 7 1.89 0.59 2.48
2013-11-05 185 67 15.9 0 1.89 0.00 1.89
2013-11-06 187 69 5.3 7 0.63 0.59 1.22
2013-11-07 195 69 21.2 0 2.52 0.00 2.52
2013-11-08 203 70 21.2 3.5 2.52 0.29 2.81
2013-11-09 212 71 23.85 3.5 2.84 0.29 3.13
2013-11-10 219 72 18.55 3.5 2.21 0.29 2.50
2013-11-11 224 73 13.25 3.5 1.58 0.29 1.87
2013-11-12 232 73 21.2 0 2.52 0.00 2.52
2013-11-13 237 74 13.25 3.5 1.58 0.29 1.87
2013-11-14 242 75 13.25 3.5 1.58 0.29 1.87
2013-11-15 247 75 13.25 0 1.58 0.00 1.58
2013-11-16 251 76 10.6 3.5 1.26 0.29 1.55
2013-11-17 255 77 10.6 3.5 1.26 0.29 1.55
2013-11-18 261 77 15.9 0 1.89 0.00 1.89
2013-11-19 271 79 26.5 7 3.15 0.59 3.74
2013-11-20 279 80 21.2 3.5 2.52 0.29 2.81
2013-11-21 288 80 23.85 0 2.84 0.00 2.84
2013-11-22 300 81 31.8 3.5 3.78 0.29 4.07
2013-11-23 308 83 21.2 7 2.52 0.59 3.11
2013-11-24 313 84 13.25 3.5 1.58 0.29 1.87



Sorry about format ..... any ideas on displaying a better format ?

Throwaway Account

May I ask who did you use as a supplier?