Very interested in tracking my COP, and optimizing, and comparing to others. I’m in California, with Chiltrix CX50 heatpump, running for DHW+radiant (& a couple FCUs).
Should I expect any fundamental problems setting up the OEM hardware(with heatmeter) for my system (here in US)?
I don’t see any US members there, only UK and maybe one from Italy. Any comment on why?
Here is report I put together on my system, with COP measurements (using hp controller’s internal temp and flow sensors). My analysis compares measured COP to manufacturer’s published data, and dependence on compressor speed, fan speed, and temp:
Compressor speed dependence is interesting (to me) - does your system allow tracking of that?
I am somewhat interested to separate radiant COP from DHW COP (separate time lines for each) and power consumption for each. Can that be done without too much added expense?
What hardware bundle or selection do you recommend?
I don’t think so. The OEM kit manufactured in the UK (the current versions of the emonPi and the emonTx) get their power either from 5 V USB or the emonVs - the latter has a universal power supply so only needs the appropriate plug fitted (buy the ‘no plug’ version). Line frequency is set in software when necessary. However, you might want to source the heat meter locally, as the ones in the OEM shop (and included in the bundle) are 240 V 50/60 Hz mains or low voltage 12 – 42 V DC or 12 – 36 V 50/60Hz AC external power supply, according to the data sheet on the Shop page.
Why not? It’s open to anyone.
Maybe heat pumps aren’t as popular where you are? One of my moderator colleagues lives in Oklahoma - maybe @Bill.Thomson can offer an explanation.
As it says in the FAQ: Please don’t link to files on external sites. Unlike others, we want you to attach your screenshots, log files, etc to your post. If the external site goes away, the material is likely to be lost forever. If that happens, when someone reads your post, your question and our answer will have little or no value.
If you need to post more than one attachment, tell us you have more information to post, and we’ll change your user account settings to enable you to do so. I’ve done that so you should be able to post that information now.
I can’t answer the other couple of questions, so I’ll leave those in the air for someone who knows more to pick up.
That shouldn’t be a problem as the North American split-phase residential electric
system is a 240 Volt system, i.e. 120 - 0 - 120 Volts. Even if there are no large
electrical loads in the house, 240 VAC is still available at the Load Center.
If that were the case - no 240 V loads - then new wiring might be needed.
A 24 V control transformer (common HVAC item) is one option.
A 12 VDC power supply (low cost and widely available) would be yet another option.
My guess would be that it gets too cold in too much of the US, for them to be practical.
That’s strictly a guess. I have no concrete evidence to substantiate it.
Robert, Bill,
Thanks for your comments. Do you recommend I get the ‘bundle’ (emonHP) + emonVs, or do I need to get all the components separately(in order to get the correct features)?
Also, as asked above, is it possible to separately get timelines for DHW and radiant? Can the system handle 2 separate heatmeters (If I need one on each of radiant and DHW)?
Hi Glen. You should be fine with one heat meter as long as it is positioned before the 3-way-valve that switches the flow between DHW and heating. The flag to assign the data to DHW or heating often comes from having a current sensor around the relays switching the valve. I’m unsure which OEM component specifically would be used for that though, maybe someone else can chime in.
thanks, but I have space/geometry constraints and may not be able to put heatmeter /flowmeter before the diverter. I may need to put downstream…so in this case can OEM system handle 2 flow meters?
Glen, the default Axioma Qalcosonic E4 heat meter supplied with the level 3 HP monitoring bundle is configured to be installed on the primary flow (before/upstream of the 3-way valve), but there are other heat meters that can go on the primary return (after/downstream of the heating/DHW common tee) - should you happened to have a bit more space here to install?
Its definitely not common to have air-to-water heat pumps around here. Air-to-air are taking off. But it would be nice to see some more NA heatpump models listed to compare to. I almost went with Chiltrix.
I’m using my heatpump’s internal heat measurements, so its not ‘MID’. I may get proper flow metering in the future.
Hi Josh
Sorry - that link doesn’t work. Can you try again? What HP did you end with?
Why is it you think AWHPs are not common there in Ontario? I think of forced air as a US (and now Canadian) approach, and not common in most other countries.
hmm… don’t know why the link wouldn’t work. To see it on the homepage list, you need to set the “stats time period” to at most 30 days (haven’t been up there long, this will be my first winter), and enable the “show systems with: heatpump integration” on the left side. Then scroll all the way to the bottom! Can’t come close to the impressive COPs at the top.
I went with the ThermAtlantic DX2W which pairs with a Gree Flexx central unit. I chose it because it is a split system, so no water goes outside, which I feel is important with design temperature of -23C (-9.5F). Most available were monoblocs, but then would require glycol.
Its nearly all forced air here, big natural gas furnaces, and those are easily convertible to hybrid systems by replacing the air conditioner with air-air heat pump.
But I was working with worst of all worlds - the house I bought was all electric resistance baseboard heaters. I opted to install hydronic heated floors and radiators because running PEX was simpler and less invasive than installing ducts. But it was a challenge, there is no industry/installer knowledge of air-to-water heatpumps, so I had to design the system myself and convince someone to help install it.
Hi Josh, great to see systems from other countries on HPM.
You’re system appears to be cycling a quite a bit - maybe due to the relatively mild outside temperatures and load if your design outside temperature is -23C. Is it a modern/well insulated house?
Interested to know how your is system controlled (zone/room thermostats, weather compensation etc) and how it’s connected up (direct, buffer/low loss header, do you have pump/mixer on the UFH (hydronic) manifold etc and what’s the floor make up (screed/slab, suspended with reflector plates etc) and system volume? Also, how close is the HP size/output to the actual design peak load - dose it have a back-up heater?
*Sorry, for getting away from Glen’s original post, maybe split it.
Edit, I’ve just found your system summary which answers a lot of the above!
I wish I could stop its cycling… that’s a work in progress. The DX2W manufacturer spec’ed a single speed pump that handles 10 kW heat, which is what this unit outputs in mild weather. The Gree is supposed to modulate based on the condition of the return refrigerant, but I may need to slow down the circulator/extract less heat from the refrigerant to trigger that.
Well at least the buffer keeps the unit running for at least 10 minutes. It should run much longer as it gets colder out.
Its rated output at design conditions is almost 100% match with heat loss (7kW). I would have preferred to undersize it a bit, but they don’t come any smaller. There is a backup electric boiler.
The floor is Warmboard-R panels, I run floor and rads at the same temp, which should be around 40C flow at design. Will be tuning the weather comp curve this winter.
edit: the house is actually not very well insulated compared to modern standards here. Our walls get cold and my hope is the radiant heating will counteract that comfort-wise
Josh, I can see your data now ( sorry, I didn’t have heatpump integration selected). What does ‘heatpump integration’ mean?
Do I understand correctly, you have hydronic system with outdoor compressor, split system(not monobloc) so no water outside, refrigerant lines run indoors to ThermAtlantic DX2W, which is perhaps just a plate heat-exchanger btw the water side and refrigerant side? or something fancier? I assume needed to have someone braze in the line sets? And your system still has buffer tank I assume?
What refrigerant does your system use?
(I agree the glycol is a nuisance.)
My install is all DIY too. (Full report including COPs and compressor dependence etc is in a sharable 50page google doc that I tried to post earlier in the thread. I am curious about compressor dependence and other folks experience there, will pursue that in other thread.)
You understand perfectly. Nothing fancy, the indoor unit is just a heat exchanger and some controls + sensors. Yes, buffer is required to reduce short cycling. It uses R410A.
“heatpump integration” means I use the heatpump’s integrated heat metering instead of a calibrated third-party monitor.
Josh, depending on your UFH/Rad layout and zone control requirements, you could possibly reduce some cycling by doing away with the buffer and secondary pump etc, or even repipe it in series as a volumiser if need be. Ideally the remaining primary pump would be controlled by deltaT (~5degC) between flow and return, with well dialled in weather compensation to adjust flow temperature. But it would require an open circuit approach to enough of the system to ensure adequate flow. Nice and simple and potentially very efficient!
A complicating factor is I’m trying to use this for cooling as well. It buffers the chilled water, there is a mixing valve to keep distribution side above dewpoint. But I have a plan that involves a by-pass or two and some custom controls
Kindly explanation (or point me to info on) setting up integrated heat metering? I couldn’t figure how to pull the data out of my controller (and Chiltrix wouldn’t give me any info). Is it normal that that info can be extracted for other or all brands? I would love if I could do that without too much pain. (All my COP tracking I’ve been doing manually with paper and pencil & spreadsheet - I"m embarrassed to say.)
The ThermAtlantic unit has a modbusTCP interface that surfaces all its data, so I wrote some code that polls the heat output and flow temps.
I know Chiltrix has a modbus serial interface, I asked them about it when getting the quote, but I don’t know the details about it or what data they make available. You’d have to ask them for the docs.
