navitron
 
Renewable Energy and Sustainability Forum
Welcome, Guest. Please login or register.

Login with username, password and session length
News: Anyone wishing to register as a new member on the forum is strongly recommended to use a "proper" email address. Following continuous spam/hack attempts on the forum, "disposable" email addresses like Gmail, Yahoo and Hotmail tend to be viewed with suspicion, and the application rejected if there is any doubt whatsoever
 
Recent Articles: Navitron Partners With Solax to Help Create A More Sustainable Future | Navitron Calls for Increased Carbon Footprint Reduction In Light of Earth Overshoot Day | A plea from The David School - Issue 18
   Home   Help Search Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: Heat Pump background /idle power consumption  (Read 1718 times)
Countrypaul
Hero Member
*****
Offline Offline

Posts: 1823


« on: August 11, 2020, 01:55:25 PM »

We have an 11.2kW Ecodan ASHP, in recent weeks this has not been required for either hot water or space heating yet it is still consuming a significant amount of electricity, around 1/2kWh per day which I assume is its background usage. I have tried searching online but not found anything concrete, however I have found some heat Pump owners that appear to have background loads as high as 275W (24/7) which seems absolutely crazy.

Has anyone on here got any figures for what their HP uses?

At ths time of year I could probably turn it off, but as soon as I do and we get a couple of poor sunshine days, my life will be made miserable  whistlie

1/2 kWh per day at present is probably <8p /day so not worth me taking the risk of having insufficient hot water.
Logged
Philip R
Hero Member
*****
Offline Offline

Posts: 1786

South Cheshire


« Reply #1 on: August 11, 2020, 02:54:12 PM »

I went looking on the internet. Seems that several brands of HP have high quiescent power consumption that adds up to quite a chunk of energy that has to be paid for.
Seems to be heaters used to keep the compressor warm.


Have a read of these comments :  http://johncantorheatpumps.blogspot.com/2013/08/stand-by-power-and-air-source-heat-pumps.html

Logged
marshman
Hero Member
*****
Online Online

Posts: 1046


WWW
« Reply #2 on: August 11, 2020, 02:57:36 PM »

I know it is not Air Source, but my 10kW GSHP has consumed 0, (zero), kWh since 16th May 2020 when it last was used for DHW.  It does fire up the circulation pumps once every so often, but only for a few minutes,  not sure what protocol it is using, I only know this because I have heard them on occasion.

Can't think why an ASHP would consume anything if there is no heat demand - unless there are circulation pumps running on the wet side - assuming an Air to Water - in which case maybe a simple thermostat to shut the power off over a certain room temp would suffice.

Roger
Logged

3.15kWpk (15xSharp ND210)/SB3000. & 3.675kWpk (15 x Suntech 245WD)/SB4000TL, 10kW GSHP driving Wirsbo underfloor heating from 1200m ground loops. 10' x 7' solar wall (experimental). Clearview 650 Wood Burning Stove. MHRV - diy retrofit. Triple glazing.
Philip R
Hero Member
*****
Offline Offline

Posts: 1786

South Cheshire


« Reply #3 on: August 11, 2020, 03:19:02 PM »

Running the pumps few a minute every day is to help prevent them from jamming.
Logged
benseb
Jr. Member
**
Offline Offline

Posts: 76


« Reply #4 on: August 14, 2020, 07:19:52 PM »

Aparently there’s something to do with the way the ASHP uses a reactive load that shows up as high standby consumption but doesn’t actually use that much

When I’ve Monitored our Ecodan the power sits about 200w but the flow switches between “usage” and “generation” so probably nets close to zero


Looking at the app we’re using approx 400-500w per day on standby for heating.
Logged
Countrypaul
Hero Member
*****
Offline Offline

Posts: 1823


« Reply #5 on: August 15, 2020, 12:00:57 AM »

Having checked with Mitsubishi, the Ecodan does keep the crankcase warm with a heater which accounts for the 1/2kHw per day we are seeing as a standby load - this doesn't appear to be mentioned in any of the literature that came with it. They have advised that it we turn the entire Ho off, we should turn the outside unit on for 2-3 hours first then switch it off turn the indoor person on followed by the outdoor unit in order that the crankcase is warm before the control system is started.

having read more around the sbject we are lucky some ASHP appear to use upto 275W on standby  Shocked Shocked
Logged
knighty
Hero Member
*****
Offline Offline

Posts: 2879


« Reply #6 on: August 15, 2020, 12:12:45 AM »

the crank case heater is to stop the refrigerant gas dissolving into the oil...

if you check what kind of gas your system has in (should be on a sticker somewhere)

you could check the temperature needed to keep it out of the oil, and then fit a thermostat to keep the compressor above that temperature?


you might even be able to put it on a timer? - it'll need googling to check but I wouldn't be surprised in an hour a day to get the gas out of the oil would do?
Logged
DonL
Hero Member
*****
Offline Offline

Posts: 577


« Reply #7 on: August 15, 2020, 09:03:35 PM »

I have been logging my Panasonic ASHP consumption and it does no heating all summer as I do not use it for hot water. In the summer months it uses between 10 and 14 kWh per month (or about 14 to 20w if it is drawing power constantly).
Logged

Schuco solar hot water - 3300kWh/annum, 16 BP 4175N PV panels - 2.8kWp, log burner and back boiler and 18 Ying Li 235 PV panels - 4.2kWp, 42kW ground mount PV, 9kW Panasonic ASHP, 40kWh Nissan Leaf
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.20 | SMF © 2013, Simple Machines
SMFAds for Free Forums
Simple Audio Video Embedder
Valid XHTML 1.0! Valid CSS!