Air source heat pum...
 
Notifications
Clear all

Air source heat pump performance

525 Posts
28 Users
418 Likes
53.7 K Views
(@derek-m)
Illustrious Member Moderator
13544 kWhs
Veteran Expert
Joined: 3 years ago
Posts: 4143
 

Hi Jeff, 

You don't have to be Einstein to know that cold water has a cooling effect, though I am very pleased to see that research is being carried out to quantify how much of an effect it does have.

Now they need to investigate coatings that reduce the heat loss, or ways to prevent the water getting onto the walls and windows in the first place. We are fortunate to have quite wide soffit boards along the sides of our bungalow, so it would have to be blowing a gale for rain to reach the brickwork.

 


   
Jeff and Jeff reacted
ReplyQuote
 DanT
(@dant)
Estimable Member Member
0 kWhs
Joined: 3 years ago
Posts: 35
 

@derek-m thanks for this, I didn't know the inverter could give us that data. I've mapped out each day now since January 1st, and have a view of our average kWh generated via the panels per month, considering how rubbish the weather was in May, its not surprising its lower than April - tho the bank holiday was ace. We have 8 panels, just a small 2W system, yep they are south facing.

image
image

@mars - I see above you mentioning reducing the flow rate, is this the hot water tank temp? 


   
ReplyQuote
(@derek-m)
Illustrious Member Moderator
13544 kWhs
Veteran Expert
Joined: 3 years ago
Posts: 4143
 

No problem Dan, if there is anything else about which you are not certain then just ask.


   
ReplyQuote



(@kev-m)
Famed Member Moderator
5550 kWhs
Joined: 3 years ago
Posts: 1299
 
Posted by: @editor

@derek-m, I think we are heading that way, especially if electricity tariffs don't start to come down. 

I pulled our data for this year so far, and it's scary to see how much power we've used: https://myhomefarm.co.uk/its-not-been-an-efficient-year-for-our-ashp-so-far

This winter and spring has been a lot colder than last year, and it's really interesting to see the correlation between ambient temperature and ASHP consumption. 

Our next step in this journey is to now drop our consumption. The new K3s have definitely addressed our cold rooms, and everything is now coming to temperature. I think that we'll try and drop the flow rate to 40C, and see if that helps. 

I dropped ours to 40C on May25, 2021, but the outside temperatures have gone up and I haven't seen a considerable difference, but let's see what happens.

40C

Very interesting.  Our usage pattern is similar, but 55-60% of yours.  Probably down to relative house sizes as we're not jumper people either!  I also haven't made any adjustments yet; my system is still set up as it was installed with 50 deg flow and weather compensation.

Looking at your monthly figures on myhomefarm, I'm quite encouraged. If I use your winter monthly pattern and my April/May numbers, my likely winter kWh consumption is definitely something I could live with and a lot less than the old storage heaters both in terms of money and CO2.  


   
ReplyQuote
(@derek-m)
Illustrious Member Moderator
13544 kWhs
Veteran Expert
Joined: 3 years ago
Posts: 4143
 

Hi Dan,

As a test you could try removing the 5am to 7am water heating schedule and see what difference it makes to your electricity consumption and supply of hot water.

Mars was referring to the water flow temperature, which is the temperature of the water coming from the ASHP. You should try to operate your ASHP with the lowest temperature setting, since this improves the overall efficiency of the system.


   
ReplyQuote
(@derek-m)
Illustrious Member Moderator
13544 kWhs
Veteran Expert
Joined: 3 years ago
Posts: 4143
 

Hi Kev,

It would be interesting to see how well the weather compensation works. On your system does it show the actual water flow temperature? If the weather compensation is functioning, it should have lowered the water flow temperature from the initial 50C, down to probably the mid to low 30's. Obviously, you may have to get up around 4am when your ASHP may be running, but that's okay since I don't have a problem with that. 😍 


   
ReplyQuote
(@kev-m)
Famed Member Moderator
5550 kWhs
Joined: 3 years ago
Posts: 1299
 

@derek-m, I'll have a look when it cools down enough for the heating to kick in.  It won't be at 4 in the morning though!!


   
Mars and Mars reacted
ReplyQuote
JulianC
(@julianc)
Prominent Member Member
1022 kWhs
Joined: 3 years ago
Posts: 304
 

Maybe it’s just us hardy Midlanders, 😋 but surely your ASHP heating is off now. For the summer?  Mine is also off for hot water, as I have solar PV. But I could understand why others need the ASHP running for hot water demand. 
I called Daikin support to ask what the standby electric usage was for my HP. They didn’t know specifically 😳, but said it was low. Meaning a kW or 2 a day to keep the compressor functioning. I’m keeping an eye on the meter usage

Daikin Altherma 3H HT 18kW ASHP with Mixergy h/w cylinder; 4kW solar PV with Solic 200 electric diverter; Honda e and Hyundai Ioniq 5 P45 electric vehicles with Myenergi Zappi mk1 charger


   
Mars and Mars reacted
ReplyQuote
(@kev-m)
Famed Member Moderator
5550 kWhs
Joined: 3 years ago
Posts: 1299
 

Hardy?  You're all soft English to me 😉 

It's set to 21 degrees morning/evening so has been off for a couple of days now but will come on in the morning if it's cooler at night.  I might re-think whether we can live with it a degree or two less.       


   
Mars and Mars reacted
ReplyQuote



JulianC
(@julianc)
Prominent Member Member
1022 kWhs
Joined: 3 years ago
Posts: 304
 

Haha @kev-m. 21C. You need to wear a wool jumper 😂

But you are right, different parts of the country at different temperatures  

We are lucky to get quite a bit of solar gain.  Which we can also manage quite well.

Plus chasing Mrs J around the house keeps us warm 😉

 

Daikin Altherma 3H HT 18kW ASHP with Mixergy h/w cylinder; 4kW solar PV with Solic 200 electric diverter; Honda e and Hyundai Ioniq 5 P45 electric vehicles with Myenergi Zappi mk1 charger


   
Mars and Mars reacted
ReplyQuote
 DanT
(@dant)
Estimable Member Member
0 kWhs
Joined: 3 years ago
Posts: 35
 

@julianc 

Hi Julian

With this product, I assume it still only diverts the excess to the water tank. i.e. on a sunny day, the solar let's say would be providing the power for the dishwasher, and then any excess would be diverted to the hot water tank?

It wouldn't divert all the power to the hot water tank, bypassing powering the dishwasher, right?


   
Mars and Mars reacted
ReplyQuote
Mars
 Mars
(@editor)
Illustrious Member Admin
16491 kWhs
Veteran
Joined: 3 years ago
Posts: 2296
Topic starter  
Posted by: @julianc

Maybe it’s just us hardy Midlanders, 😋 but surely your ASHP heating is off now. For the summer?  Mine is also off for hot water, as I have solar PV. But I could understand why others need the ASHP running for hot water demand. 
I called Daikin support to ask what the standby electric usage was for my HP. They didn’t know specifically 😳, but said it was low. Meaning a kW or 2 a day to keep the compressor functioning. I’m keeping an eye on the meter usage

Our heating was still coming in the early hours of the morning last week, so we've just switched it off at the panel now. Hot water is being exclusively reheated by solar PV via the iBoost. As a result our electricity consumption has plummeted. 2021 has been a heavy year. 

Buy Bodge Buster – Homeowner Air Source Heat Pump Installation Guide: https://amzn.to/3NVndlU

Follow our sustainability journey at My Home Farm: https://myhomefarm.co.uk


   
JulianC and JulianC reacted
ReplyQuote
Page 16 / 44
Share:

Join Us!

Latest Posts

x  Powerful Protection for WordPress, from Shield Security
This Site Is Protected By
Shield Security