Earth NotesIs there a good study of which #heatpump #spaceHeat control schemes are commonly used in Europe? Help! B^>
Eg on-off / bang-bang vs weather compensation vs load compensation vs TPI vs what?
SPECIFIC IKCHi there! Primarily central thermostat and simple on/off cycling are the legacy control systems which seem to still be used in some new heat pump installs.
More heating systems are being fitted now with room by room control via manual TRV (restrictor) or smart TRV (thermostatic switch). Gas boilers have been historically badly understood as heating devices in terms of efficiency and poor system design which has relied unecessarily on high flow temps (because gas was cheap).
Whilst heat pumps are still being installed "badly", we are seeing a growth in direct open loop heat pump system design, with no buffer tanks or low loss headers, no thermostat or interrupting switches. Just accurate heat loss calculations used to size heat pump and emitters correctly for maximum efficiency at the lowest possible flow temperatures to maintain desired room temp. This factors in weather compensation profiles.
@info_specific I have been hoping/hearing/assuming that new UK systems were mainly weather compensation.
Are you saying that new EU systems are largely weather compensation?
Sorry for the delayed response! Hopefully some useful info here (from one of our team members):
The Heat Pump Wave: Opportunities and Challenges https://publications.jrc.ec.europa.eu/repository/bitstream/JRC134045/JRC134045_01.pdf
Reference to page 73:Rated capacity vs performance curves.
Heat pumps should have option to set performance curves, which are essentially weather compensation of flow temperature (or at least power to meet set flow temp), which needs to be set to optimum at point of install (or shortly thereafter once optimised)
The aim in setting up the control strategy for the home, is to meet heat loss at a specific outside temperature. The performance curve ramp should therefore be set on the assumed ideal to modulate effectively for the local climate.
Reality is that secondary thermostats and smart TRVs are still fitted in many instances where this system is misunderstood, and can interfere with the efficiency of a well-designed system, by causing unnecessary cycling. Less cycling, more efficiency.
@EarthOrgUK Lower flow temp, higher COP.
Also, overall sCOP includes the hot water COP and is usually lower as the hot water heating performance is lower (because it's pushing to a higher temp), BUT what is not accounted for in sCOP measurement or tracking is the overall cost per unit of heat delivered, when factoring in access to TOU tariffs. If you can charge hot water overnight at 1/3 price electricity, then DHW COP is less important, as is the space heating delivered during this window
Also, overall sCOP includes the hot water COP and is usually lower as the hot water heating performance is lower (because it's pushing to a higher temp), BUT what is not accounted for in sCOP measurement or tracking is the overall cost per unit of heat delivered, when factoring in access to TOU tariffs. If you can charge hot water overnight at 1/3 price electricity, then DHW COP is less important, as is the space heating delivered during this window
@EarthOrgUK I'd be interested to see a new metric like a "cost performance factor" based on the end user cost per kWh delivered.
This is where smart controls like https://www.homelyenergy.com/ come in.
This controller will blend weather comp with TOU pricing strategies, actual weather (driving wind, rain, solar gain in winter), and controls the heat pump via modulation, not a switch.
This is where smart controls like https://www.homelyenergy.com/ come in.
This controller will blend weather comp with TOU pricing strategies, actual weather (driving wind, rain, solar gain in winter), and controls the heat pump via modulation, not a switch.
Homely - The smart controller that optimises Heat Pumps
Homely. The smart controller that optimises Heat Pumps. Heat your home efficiently and reduce your heating bills by up to 25%. Installer? Click here Homeowner? Click here What makes Homely the smartest choice for controlling a heat pump? Reduce your heating bills by up to 25% Everything optimised, just leave it all to Homely A cosy, […]
@EarthOrgUK This is not widely adopted, but should be the default control method type (whether from Homely or a competitor) for all heat pumps in my opinion.
@info_specific Hey, thanks! A sensibly weighted cost version of CoP could be really challenging since I don't think any of the more interesting tariffs in the UK are reflecting costs (financial or full externalised)!
BTW, having difficulty finding your p73 words!