@iantelescope after Jan 2022 still trying to get a service for my grant heat pump. Registered with grant and ordered their servicing to void my warranty expiring. Still waiting though and not had a response from my last email to them so guessing it's still a resource problem re qualified staff available 🤷‍♂️ Although happy-ish with my Ashp I'm sure there could be tweaks to make it more efficient.

Hi All,

Measure Your Heat Pump  Efficiency ............. Get Sharky !!

My Heat Pump installation came with a unwanted Heat Exchanger fitted between my Samsung  Heat Pump and the House Radiator circuit.

From measurements with a "Sharky" water  power meter I have measured the actual output power on the Radiator circuit .

My Heat Exchanger with the added pipes , filters and motor,  looses 26% of the power in passing through the Heat Exchanger and it's pipes!

All Heat Pumps , with Heat Exchangers, should be fitted with , in  water, power meters!

From bitter experience ,for Samsung Heat Pumps ...............Do not rely on  the front panel COP figures!

Measure the actual output COP figures  yourself!

ian

@iantelescope - can you elaborate a bit? What 'Sharky' did you use, how did you install it, and what actual data did you get, and how did that lead to a 26% loss across the heat exchanger?

I also think we need to careful about terminology here. I am not sure they are actually losses, more inefficiencies or bottlenecks. In other words, the PHE acts as a sort of throttle or bottleneck, limiting transfer of heat from the heat pump to the rad circuit. Given my PHA is in the airing cupboard, any 'losses' will end up heating the airing cupboard/house so they are not actually lost.

@iantelescope are you able to measure the temp difference between the the flow to the Heat Exchanger from the HP and the flow from the heat exchanger to the emitters.

Alternatively can you tell whether the heat exchanger has been plumbed so that the flows on either side go in the same direction, or in opposite directions.

Sadly its not uncommon to plumb heat exchangers so that the flows or either side go in the same direction. They should go in opposite directions. If you get this wrong there will be at least an additional 5C temp drop across the heat exchanger, which will instantly reduce COP by 10% or more. Furthermore the 10% lost is not manifested as heat lost from the system to the building, it results in a reduction in the efficiency of the heat pump itself.

Posted by: @cathoderay

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@iantelescope - can you elaborate a bit? What 'Sharky' did you use, how did you install it, and what actual data did you get, and how did that lead to a 26% loss across the heat exchanger?

I also think we need to careful about terminology here. I am not sure they are actually losses, more inefficiencies or bottlenecks. In other words, the PHE acts as a sort of throttle or bottleneck, limiting transfer of heat from the heat pump to the rad circuit. Given my PHA is in the airing cupboard, any 'losses' will end up heating the airing cupboard/house so they are not actually lost.

 

I believe that you are correct, since it is not an actual loss of energy, but more a reduction in efficiency at the actual heat pump.

Because the water temperature required at the heat emitters should always be what is necessary to meet the heat demand, any reduction in temperature across a heat exchanger or buffer tank will need to be accommodated by an increase in the Leaving Water Temperature (LWT) from the heat pump. If under specified operating conditions, without a heat exchanger or buffer tank installed, a heat pump utilises 1kW of electrical energy to absorb 2kW of thermal energy from the outside air, and hence outputs 3kW of thermal energy to the heat emitters. The system therefore has an overall COP of 3.

If a heat exchanger or buffer tank is now introduced within the above system, to meet the required water temperature at the heat emitters it may be necessary for the LWT to be increased by 5C or so. To produce the higher LWT the heat pump compressor will need to work harder to increase the refrigerant gas pressure and temperature. If the heat pump now draws 1.1kW of electrical energy to absorb 1.9kW from the outside air, producing an output of 3kW of thermal energy, the system COP will now be reduced to 2.73.

@cathoderay 

Hi,

My Samsung Heat Pump.............measurement of power, Energy and Temperatures.

1 Energy Measurements

I have fitted a "Sharky" , in water, heat power  meter to the radiator water pipes with the Temperature sensors some 2 m below the power sensor head.

The Actual Cop , and the losses, are obtained from the Samsung front panel "Daily Energy Generated " and the Daily Energy displayed on the Sharky.

2 Electrical Power Measurements

I have fitted a energy and power meter to the common Heat Pump and Tank power lines through two CT Transformers.

The Electrical power readings are stored on a Memory card for display on a PC.

3 Temperature Measurements

I have fitted four K type Temperature recording  sensors to :

1) The Heat Pump Input water pipe.

2) The Heat Pump water return pipe.

3) The Radiator , post Heat Exchanger, water pipe.

4) The Radiator , post Heat Exchanger return.

The Sharky returns the Radiator output and return Temperatures .

4 Water Flow rates Measurements

The Heat Pump flow rate is measured by a "SIKA" Flow rate meter , displaying on the Samsung Front panel.

The Radiator flow rate is measured by the "Sharky" , in water sensor.

5 Loss Measurements

I have compared the Energy Consumed when fitted with a  Worcester-Bosch Gas boiler with the energy consumed by the Heat Pump.

The Heat pump consumes  1/2.2,  circa 50 % of the energy compared to the Gas Boiler.

But, Electricity, is locally, 3.97   times the cost of Gas.

So, the Heat Pump represents a cost increase of (3.97/2.2) x 100 = 180 % over the Gas boiler.

So , the Heat pump, even neglecting the recent energy price increases, represents a 80% increase in my bills!

Every Real measurement confirms the losses!

6 Buffer Tank losses, Short Cycling

A 50 litre Buffer tank was fitted , some three months after the start of installation "to limit Short -Cycling ".

When used, the buffer tank  Buffer increases the losses......!!!

ian

@derek-m - a succinct, and clear explanation, thank you. I think it is worth noting in your hypothetical but very possibly typical example, the actual drop in efficiency is (3 - 2.73)/3 or 9%, whereas Ian believes his 'losses' are 26%, corresponding to a drop in COP from, to use your starting point, say 3 to around 2.2, ie enough to tighten the sphincters somewhat. That's why I asked for more detail on how he got to the 26% figure. 

I'm also interested in the nitty gritty because i was going to do a post soon on the next stage of my heat pump monitoring, in particular, what to measure, and how and where, while keeping costs withing sensible bounds.

@iantelescope - you have posted while I was writing the above, thanks for the details. I should also add that these real world increases in costs (or failure of savings to appear, as in my case, as a result of switching from a timed fossil fuel boiler to a 24/7 heat pump) are worth documenting here, so that others can get a more shall we say rounded view of what is and isn't achievable in the real world before they commit to a heat pump. That is not to say I am against heat pumps, instead I just urge a bit of pragmatism based on real world experience.  

@iantelescope

How do you intend to rectify the problems within your system? Did we discuss these problems some time ago?

Posted by: @cathoderay

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@derek-m - a succinct, and clear explanation, thank you. I think it is worth noting in your hypothetical but very possibly typical example, the actual drop in efficiency is (3 - 2.73)/3 or 9%, whereas Ian believes his 'losses' are 26%, corresponding to a drop in COP from, to use your starting point, say 3 to around 2.2, ie enough to tighten the sphincters somewhat. That's why I asked for more detail on how he got to the 26% figure. 

I'm also interested in the nitty gritty because i was going to do a post soon on the next stage of my heat pump monitoring, in particular, what to measure, and how and where, while keeping costs withing sensible bounds.

@iantelescope - you have posted while I was writing the above, thanks for the details. I should also add that these real world increases in costs (or failure of savings to appear, as in my case, as a result of switching from a timed fossil fuel boiler to a 24/7 heat pump) are worth documenting here, so that others can get a more shall we say rounded view of what is and isn't achievable in the real world before they commit to a heat pump. That is not to say I am against heat pumps, instead I just urge a bit of pragmatism based on real world experience.  

Yes, I had arrived at a 9% reduction in efficiency. If my understanding is correct, it would appear that Ian has both a PHE and a buffer tank installed within his system. That gets a bit closer to 26%.

@derek-m 

Politics ................and Heat Pumps !

I have recently resumed my quest to get my heat pump efficient and stable.

My "installer", Twice Struck OFF by the NIC for "incompetence" , has now been given his licence back.

The Scottish Government, HES EST, has only covered my  initial down payment costs given that my "installer" has failed to provide  valid documentation proving that my Heat Pump is working efficiently".

The NIC is , currently, trying to get my "installer" to provide the "hand over " documentation some 15 months after the start of the "installation".

I have No confidence that my "installer" has the trained staff, equipment or knowledge about Samsung Heat Pumps.

My "Annual Service" demanded by both Samsung and Telford has never been performed............................with nobody admitting responsibility.........

@iantelescope

I am sorry to hear of your woes.

Unfortunately there would appear to be no regulatory body responsible for ensuring the correct installation and commissioning of heat pumps. Maybe you should have a word with your MP.

I am surprised to also hear that your incompetent installer has once more been reinstated after previously been struck off twice. The present regulatory systems appear to be highly flawed.

@derek-m 

My MSP ( Member of the Scottish Parliament ) obtained the initial "down payment " from the Scottish Government , HES EST on Dec 15th 2022 ..................

.......despite the absence of Documentation proving that the Heat pump was then  working.

To get the remainder of the repayments , some £4000, I will still need to get confirmation that the Heat pump is working , and efficient.

A rock and a Hard place !

ian