My Heat loss calculation is about 6kW but installer insists i need a 16kW heat pump!

Sustainable Energy
21

Hi Trystan
I have been searching for the specs for the
WPYG160LJL and WSYG160DJ6
But with no Luck.
Have you any idea why ? or where they are?

Thanks

Mike

22

What is the SAP rating for the property?

23

Hi there. Yes I am monitoring the COP in real time using an Emonpi2 that I installed a couple of months ago. The Daikin does measure the overall energy consumed versus energy used so you can calculate the SCOP, but doesnā€™t give instantaneous COP.

My system has long pipe runs and uses a buffer tank and separate circulator pump for the CH and I wanted to calculate the COP of the actual heat going into the house rather than the nominal efficiency of the HO itself. So I installed temperature probes on the flow and return from/to the buffer tank. These are monitored every minute by the Emonpi2 and also calculates the DeltaT by subtracting return from flow temperature.

The circulator pump is a Wilo operating at a fixed speed when running, and the volume it pumps is displayed on the pump - just have to convert from m3/hour to litres/s. According to Sczimon from Urban Plumbers the Wilo is fairly accurate. So taking the volume (l/s) multiplied by DeltaT multiplied by 4.2 (specific heat capacity of water) the Emonpi2 calculates the heat output (kW) of the HP after the buffer. The COP then just the heat output (kW) divided by the electrical input (kW).

Thereā€™s also a calculation to determine if the heat pump is running or idle - where it still consumes 25 watts so I donā€™t record silly COP numbers when itā€™s actually not doing anything but thereā€™s still a DeltaT.

The actual COP obviously depends on the weather etc. but Iā€™m getting values between 3 and 4.5, which seems reasonable.

Hereā€™s an example from yesterday afternoon. You can see that there are big spikes on the heat pump consumption (yellow line, right-hand scale) when it decides to run the auxiliary heater for one minute a couple of times - still something wrong with the setup there I think - it should have more patience! The COP is in blue using the left hand scale. You can see it settles down to about 900 watts input and COP of 4. It switches off when the room temperature reaches the objective for the evening.

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IMG_68031290Ɨ907 98.4 KB

24

WSYG160DJ6 gives search results, WPYG160LJL should be WOYG160LJ

https://www.fujitsu-general.com/datafiles/DIS_Information%20sheet_WOYG160LJL_WOYK150-170LJL.pdf
https://www.fujitsu-general.com/eu/products/atw/split-super-highpower/wsyg160dj6-woyg160ljl.html

25

Hi! Donā€™t Know ! I will try and find out.
I wonder as itā€™s not been built yet, maybe it doesnā€™t have one yet ?

Thanks

Mike

26

Interesting ! I think at the moment Iā€™d be very happy with those numbers. going to be interesting what your SCOP will be.
I might be tempted to disconnect the immersion heater!

I have been using an EmonTx v3 for years but am looking at the Emonpi mainly because, as I was dismantling my system in my old house I think something happened and it wonā€™t power up now!
I was thinking of a full kit with the heat meter but itā€™s a bit dear! if Iā€™m stuck with an oversized Heatpump I probably wonā€™t be able to afford it. :grin:

27

Thanks for the link. I only got one page though ! I couldnā€™t see anywhere it mentions Nominal capacity. Maybe on another page?
I have tried many searches for the numbers I have but canā€™t find what I need.
Where did you get that one from?

Thanks again

Mike

28

I had one done for my new build as soon as i got planning permission.

29

Hi !
Who did you get to do the heat loss calculation ?

30

sent you PM