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Showing results for tags 'unvented'.
I'm currently researching instantaneous water heaters, and in that context I discovered that there are both unvented water heaters and vented ones. A bit more research shows that whole plumbing systems can be either vented or not. Whassa difference? Why would anyone choose one system type over the other?
It's been raining and I've been having a think this afternoon. What would happen if you reversed "W Plan" and instead of having DHW priority, you have priority to the UFH / Buffer ..? System components are : 9kw ASHP 250 litre UVC 90 litre buffer (UFH) Low temp UFH No PV My current plan was to use a simple W Plan and time the DHW to be heated by the ASHP (48c) between 01:30 and 04:30, switching to immersion to boost to 62c up to 06:30. ASHP would then kick over to the buffer and bring it up to 37c and the floor would come in at 30c from 06:00 onwards. The norm would be for the W Plan then to drop back to DHW as showers draw off the water however the talk of PHE and pre heat has made me think I need to consider this for a number of reasons. COP - the ASHP at 37c is much more efficient than at 48c Usage - using the buffer to preheat the DHW will extend its capacity, and reduce the amount of high temp cycles the ASHP needs to do ASHP cycling - the volume of water in the buffer will be 6 times that of the DHW coil so should stop short cycling and potential defrost cycles. This would need the addition of a PHE to the buffer but that is easily done - question is, is it worth it ..??