[OpenTRV-dev] [OpenTRV-interest] Storage heating, dynamic demand, and OpenTRV
Damon Hart-Davis
EMAIL ADDRESS HIDDEN
Mon Sep 8 11:44:22 BST 2014
Hi,
Thermal store generally a good idea IMHO.
But thermal losses have to be considered amongst other aspects of whole-system design: 1kWh/day losses typical for well-lagged DHW tank in UK for example, which would be ~25% of our daily use.
One of my problems is finding some way to minimise tank losses (esp in summer, and/or divert them somewhere useful in winter) and combine with heat-pump and PV. Not keen on (nor much space for) simple solar thermal as I think would be v ineffective for us in winter.
Rgds
Damon
On 8 Sep 2014, at 11:15, Stuart Poulton <EMAIL ADDRESS HIDDEN> wrote:
> Hi,
>
> Ok, that's what I thought. I'd have thought the losses with any system internally within a house would exceed to 5-10% region anyway.
>
> Obviously we SolarPV about to be installed myself all of this is more relevant, and I have been considering moving to a thermal store over DWH for example to all some benefit from excess PV generation.
>
> Cheers
>
> Stuart
>
> On 08/09/14 11:11, Damon Hart-Davis wrote:
>> Hi,
>>
>> Well, one angle I am think of is simply avoiding the distribution and transmission losses associated with having flows across the house boundary at all. ~5% to 10% depending on circs.
>>
>> Then there is the dynamic demand issue; sculpting flows to help the grid, eg *not* restricting outbound flows if grid freqency drops or at high demand and high carbon intensity times.
>>
>> Then there is the general issue of storage with intermittent generation…
>>
>> In general I think excess should be spilled to the grid to reduce other consumers’ effective CO2 emissions, but doing less spilling at a sunny noon and more towards peak demand times is clearly a good thing.
>>
>> And to be clear: our entire average daily PV generation in December is an order of magnitude below our heat demand alone then (though we have halved that demand so far), so this is not a game changer, just a tweak to assist.
>>
>> Rgds
>>
>> Damon
>>
>>
>> On 8 Sep 2014, at 11:05, Stuart Poulton <EMAIL ADDRESS HIDDEN> wrote:
>>
>>> Hi,
>>>
>>> Purely for the purposes of discussion, thinking about the UK example, what are the advantages of keeping the energy within the house, rather than making it available to others on the street.
>>>
>>> Stuart
>>>
>>>
>>> On 08/09/14 11:00, Damon Hart-Davis wrote:
>>>> Hi,
>>>>
>>>> The key thing I’m aiming for here is short-term controllability to balance second-by-second flows in/out of the house, plus storage to carry that energy to a more useful time.
>>>>
>>>> Thus an electric storage heater rather than a normal one.
>>>>
>>>> Your DHW idea is in principle fine if done right, but storage in water isn’t plausible for everyone.
>>>>
>>>> Anyhow, only a thought experiment, so good to thrash it out!
>>>>
>>>> Rgds
>>>>
>>>> Damon
>>>>
>>>>
>>>> On 8 Sep 2014, at 10:57, Bo Herrmannsen <EMAIL ADDRESS HIDDEN> wrote:
>>>>
>>>>> my thought of a tank with electric heater is simply just that i did not know any other hardware that could do the job
>>>>>
>>>>> maybe there are a electric heater you just plumb in?
>>>>>
>>>>> 2014-09-08 11:43 GMT+02:00 Damon Hart-Davis <EMAIL ADDRESS HIDDEN>:
>>>>> Hi,
>>>>>
>>>>> Sorry, not sure if I missed this one or not.
>>>>>
>>>>> My thought experiment is for situations such as mine with solar PV and ‘instant’ DHW (no tank, and no solar thermal), which I sure is not unique!
>>>>>
>>>>> Thanks for everyone’s feedback: very helpful!
>>>>>
>>>>> Rgds
>>>>>
>>>>> Damon
>>>>>
>>>>>
>>>>> On 7 Sep 2014, at 15:57, Bo Herrmannsen <EMAIL ADDRESS HIDDEN> wrote:
>>>>>
>>>>>> hmmm
>>>>>>
>>>>>> just on top of my head.... an well insulated hot water cylinder with an electric heating element in series with the rad loop..? then both the gas heater and the electric can heat up the water at the same time...
>>>>>>
>>>>>> of course you have to wire in the electric heating element so the system will not boil...
>>>>>>
>>>>>>
>>>>>> in denmark the cylinder normally hold 100 liters of water, not sure if there are space enough in an UK home for that... but if you can get them in 50 liters you could pick 2 of them and place them where there is space
>>>>>>
>>>>>>
>>>>>> but will the gas heater make hot drinking water from that same loop? if not my idea is not worth much....
>>>>>>
>>>>>>
>>>>>>
>>>>>> 2014-09-07 13:00 GMT+02:00 Damon Hart-Davis <EMAIL ADDRESS HIDDEN>:
>>>>>> Hi,
>>>>>>
>>>>>> I have a thought in the back of my mind about carefully making some use of residual exported solar PV generation in winter with highly-efficient storage heaters controllable by an extension of OpenTRV to supplement a gas-fired system. This would also help with grid balancing.
>>>>>>
>>>>>> (Yes, I am allergic to electric resistance heating in most circumstances, but if done carefully this might be virtuous.)
>>>>>>
>>>>>> Does anyone know of off-the-shelf UK storage heaters that have electronically-controllable fans/vents and that can retain the bulk of their heat for much more than a day, preferably a week.
>>>>>>
>>>>>> Rgds
>>>>>>
>>>>>> Damon
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> OpenTRV-dev mailing list
>>>>>> EMAIL ADDRESS HIDDEN
>>>>>> http://lists.opentrv.org.uk/listinfo/opentrv-dev
>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> |||||
>>>>>> @(~Ô^Ô~)@
>>>>>> -------------oOo---U---oOo-------------
>>>>>> | |
>>>>>> | Bo Herrmannsen |
>>>>>> | |
>>>>>> | |
>>>>>> | "blessed are the "cracked", |
>>>>>> | for its they who let in the light" |
>>>>>> | Ooo |
>>>>>> |_________________ooO____( )________|
>>>>>> ( ) ) /
>>>>>> \ ( (_/
>>>>>> \_)
>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> OpenTRV-interest mailing list
>>>>>> EMAIL ADDRESS HIDDEN
>>>>>> http://lists.opentrv.org.uk/listinfo/opentrv-interest
>>>>> _______________________________________________
>>>>> OpenTRV-dev mailing list
>>>>> EMAIL ADDRESS HIDDEN
>>>>> http://lists.opentrv.org.uk/listinfo/opentrv-dev
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> |||||
>>>>> @(~Ô^Ô~)@
>>>>> -------------oOo---U---oOo-------------
>>>>> | |
>>>>> | Bo Herrmannsen |
>>>>> | |
>>>>> | |
>>>>> | "blessed are the "cracked", |
>>>>> | for its they who let in the light" |
>>>>> | Ooo |
>>>>> |_________________ooO____( )________|
>>>>> ( ) ) /
>>>>> \ ( (_/
>>>>> \_)
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> OpenTRV-dev mailing list
>>>>> EMAIL ADDRESS HIDDEN
>>>>> http://lists.opentrv.org.uk/listinfo/opentrv-dev
>>>> _______________________________________________
>>>> OpenTRV-dev mailing list
>>>> EMAIL ADDRESS HIDDEN
>>>> http://lists.opentrv.org.uk/listinfo/opentrv-dev
>>> _______________________________________________
>>> OpenTRV-dev mailing list
>>> EMAIL ADDRESS HIDDEN
>>> http://lists.opentrv.org.uk/listinfo/opentrv-dev
>> _______________________________________________
>> OpenTRV-dev mailing list
>> EMAIL ADDRESS HIDDEN
>> http://lists.opentrv.org.uk/listinfo/opentrv-dev
>
> _______________________________________________
> OpenTRV-dev mailing list
> EMAIL ADDRESS HIDDEN
> http://lists.opentrv.org.uk/listinfo/opentrv-dev
More information about the OpenTRV-dev
mailing list