Hi all
I’m considering a system with two heat pumps, one monobloc for heat and the other an integrated heat pump cylinder.
Can the OEM monitor these cylinders:
I see it’s possible to have more than one electricity meter but I don’t see a multiple heat meters option.
Many thanks
It’s not possible to monitor the heat output of a heat pump cylinder, there’s nowhere to install a heat meter! So it won’t be possible to calculate the COP.
A monobloc can be easily monitored using our standard L3 bundle.
Why not use the monobloc to also heat DHW? It’s an expensive option to get a separate heat pump cylinder. The recharge time of the DHW will be much quicker using the monobloc, the integrated heat pump cylinder have very low output heat pump, so the recharge time is long.
Oops - didn’t mean to delete that.
I was thinking you could put the meter on the HW supply and a temperature sensor in the incoming cold supply…I was just wanting to correct that it would calculate tank losses correctly assuming the incoming supply temperature varied little (or would at least be good on average).
Then I wrote something about the monobloc not needing to run in summer and being able to extract heat from vented air from the house (particuarly in summer).
I’ve restored it for you.
I’m afraid that’s not possible, heat meters can’t be used on potable water and the flow measurement won’t be accurate for DHW draw off transient flow. You could put a MBUS water meter on the cold inlet to measure the amount if DHW used and strap on DS18B20 temperature sensor to inlet and outlet to measure the temperature.
I can’t see any advantage of using a heat pump water heater if you’re already installing a A2W heat pump. A heat pump water heater will get lower efficiency due to ducting the air. MVHR integration could be interesting, but it won’t produce a significant amount of cooling since energy required for DHW is quite small comparativly to space heating / cooling.
Part of this was I was considering an experiment - which is better? Yes, that would cost me, particularly if I connected the monobloc to the coil. A thought was that this setup could be a stepping stone to weaning one-self off the gas combi.
An integrated heat pump cylinder costs the same as a pre-plumbed heat pump cylinder. I’m not doing a system design myself (at least I haven’t so far) so maybe that’s not a fair comparison for a pared-down simple design. Agreed there’s the ducting to fiddle about with.
With the tank in the loft in a four-in-a-block (2x2 flats, common in Scotland) there’s quite a loop from the ASHP location - will the losses be a lot less than a short bit of ducting?
Specifically to the monitoring question. It sounds like there’s a way.
Regarding my two very similar replies. Was I right the first time - this method of calculating the energy required to deliver hot water includes tank losses. I understand this differs from the standard emonHP method which calculates the heat delivered to the tank (and the CoP of that).
Back to my bullets. Are these right? (My expected answers in italics):
Yes, it should be possible to estimate COP
Correct, there is no off the shelf solution for this, it will need to be a DIY setup
Yes, that’s correct
Another thing that caught my eye regarding integrated HP cylinders was that several have smart contacts to allow boost or load shedding. Of course there are official and unofficial modbus solutions for ASHPs, I thought the out-of-the-box support for smart control was good!
Our install is similar with a close to 36m return journey from heat pump to cylinder. Although when heating the cylinder via ASHP, got a good CoP, the actual energy used was high. I now only use the immersion heater, it isn’t really costing any more.
A heat pump integrated cylinder (that isn’t a coated carbon steel, which I would avoid) aren’t cheap, they are big and recovery time is multiple hours. A direct immersion cylinder is cheap, they can be small just by heating to high temperature. On a decent tariff can be as cheap to heat hot water as a combi.