small heat pump

  • wizzo227's Avatar
    Level 13
    Sun this morning on the rooftop solar photovoltaics is generating enough to run for free the small air source heat pump. It did not get much use last week in the gloomy weather. The CoP (the "efficiency" number near 300%) of about 3 for this ten year old heat pump being less than the p/kWh unit price ratio of electricity/gas makes it Not A Bill Saver to run it unless at least a useful fraction of the electricity going into it is free from local solar, so for much of last week I used the Normally Off combi gas boiler when necessary.

    Today starts the morning on 100% locally generated solar electricity; completely free to use the small heat pump. The living room started this sunny morning at 13C.

    9am to 12 noon used 1.8 kWh of electricity and got the single room to >20C with some useful heat going to the hall through the deliberately open door.
    Last edited by DebF_EONNext; 27-03-23 at 18:22.
  • 8 Replies

  • Best Answer

    AndyThornton's Avatar
    Level 1
    Best Answer
    @meldrewreborn
    Please give particular examples of what you like. I've just looked at https://getmodnow.com and those particular machines, whilst having all the "right" words in the sales pitch, are certain to be an unhelpful distraction from home energy decarbonisation, which is overdue. There will be remote mining outposts overseas who buy those instead of going solar so that they can greenwash their brochure, those won't be seen anywhere which has national grid electricity because they won't be free to run, even if they do use slightly less bottled gas than plain burn. Some fossil gas executives might decide to pay extra for such machinery to prove a point, but no sane energy user should want to.

    Don't let readers forget, that as we approach summer, buying bigger better machines is an expensive distraction from efforts to decarbonise heating by comparison to "turn it off! stupid".
    Decarbonizing home energy involves reducing or eliminating the use of fossil fuels for heating, cooling and generating electricity in our homes. This can be achieved through a combination of measures, such as improved insulation, the use of renewable energy sources such as solar panels or wind turbines, and the use of energy efficient devices. energy saving.
    By decarbonizing our homes, we can reduce our carbon footprint and contribute to climate change mitigation. This is important because the burning of fossil fuels releases greenhouse gases such as carbon dioxide into the atmosphere, which contributes to global warming and its associated effects, such as sea level rise, climate change events. more frequent and severe heatwaves as well as more intense storms.
    In terms of energy-efficient appliances, choosing products with high energy efficiency ratings can help reduce energy consumption and associated greenhouse gas emissions. This includes appliances such as refrigerators, washers and dryers. I hope this information helps you
  • DebF_EONNext's Avatar
    Community Coordinator
    Hey @wizzo227,

    I don't really know much about heat pumps if I'm honest, it's not something I have ever really thought about or come across really. Other than what @Han_EONNext & @PeterT_EONNext have posted in the heat pumps section and having a heat pump tumble drier I don't really have much to go on, but I would love to learn more.

    I heat my home solely through wood/coal (using coal I imagine this will have a massive impact on my CO2 emissions) so how does a heat pump compare?

    What is your current set up, I see you mentioned solar there so is your heat pump solar assisted and if so how does this compare with using just solar? Are you able to add some pics to show us your set up so we can see what it all looks like?

    We used to have solar panels however when they died our Landlord decided not to replace them (they were very old ones with the tubes, not the panels you get now), we used to get between 4-6 months hot water & underfloor heating from them, how does this compare with a heat pump in terms of efficiency?
    Last edited by DebF_EONNext; 20-03-23 at 13:35. Reason: random , between lines!
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  • wizzo227's Avatar
    Level 13
    Deb,
    Coal burning is really bad, but a billion foreigners all have to, while making cheap stuff for you to buy in the shops. Hopefully you can just not light your coal for the rest of the summer. Do keep some wood piled up drying, since burning that only releases CO2 captured by the growth of it, and it is nice for a cosy evening in. If you can plant some trees somewhere then good, and if you always collect on foot with saw and wheelbarrow then good. Any other route to bring in wood costs the carbon emissions of transporting it.

    My heat pump is an ordinary 'air conditioner' type for one room. It gets two types of solar assist:
    i) the collector is located in the sunniest warmest corner of the garden to the south of the house.
    ii) I preferentially wait for solar photovoltaic electricity generation off the roof before switching it on.

    Today it is 13C outside and not at all sunny, with insufficient 0.2kW household net generation. I would only switch on the heat pump if I got really cold. Since it is 18C indoors at present, I'll use it a little bit only if the weather brightens up.

    economics : CoP about 3
    heat pump minus surplus photovoltaic generation costs 0.5 kW(electric) to be bought [for 0.7 kW(electric), heap pump use] getting 2.1 kW(thermal), all to air heating in the living room.

    IF 18C were too cold, gas central heating would cost more pennies per kWh and a lot more per-kWh-at-living-room, so the present heating plan is to switch on the heat pump if necessary, instead of using the normally-OFF gas central heating.

    Also in the heating plan, IF feeling a bit cold,
    THEN go for a walk around the block. Thats what I'll do next.
    Last edited by wizzo227; 20-03-23 at 15:18.
  • meldrewreborn's Avatar
    Level 81
    I’ve been reading about gas powered heat pumps, which currently only have a limited application in the UK. But they have the advantages of electric heat pumps in terms of energy efficiency, plus use of heat from operation, plus lower fuel price. Seems like an ideal solution to the matter of getting enough electricity generated - with these the existing gas grid is used. While still consuming fossil fuel, they are apparently much more efficient than condensing gas boilers.
    I think these will be more popular than electric heat pumps once they gain market momentum.
    Current Eon Next and EDF customer, ex Zog and Symbio. Don't think dual fuel saves money and don't like smart meters. Chronologically Gifted. If I offend let me know by private message, but I’ll continue to express my opinions nonetheless.
  • wizzo227's Avatar
    Level 13
    @meldrewreborn
    Please give particular examples of what you like. I've just looked at https://www.yanmar.com/global/energy/ghp/ and those particular machines, whilst having all the "right" words in the sales pitch, are certain to be an unhelpful distraction from home energy decarbonisation, which is overdue. There will be remote mining outposts overseas who buy those instead of going solar so that they can greenwash their brochure, those won't be seen anywhere which has national grid electricity because they won't be free to run, even if they do use slightly less bottled gas than plain burn. Some fossil gas executives might decide to pay extra for such machinery to prove a point, but no sane energy user should want to.

    Don't let readers forget, that as we approach summer, buying bigger better machines is an expensive distraction from efforts to decarbonise heating by comparison to "turn it off! stupid".
  • meldrewreborn's Avatar
    Level 81
    @wizzo227

    In the transition from fossil fuels to green energy there will be stages, stepping stones if you like, towards the utopian target.

    Cars are a current example. A hybrid vehicle uses fossil fuel, but has all the convenience in refuelling that a pure electric vehicle doesn’t. A hybrid offers much improved MPG over a normal car. The environmentalists don’t like hybrids because they still use some fossil fuel, and would prefer electric vehicles instead.

    Leaving aside the fact that 40+% of our electricity is generated from gas and the efficiency losses between generation and consumption of electricity, the plain fact is that electric vehicles remain niche while hybrids are favoured by the buying public. For many the hybrid is a step in the right direction. I see the gas powered heat pump in the same light.

    There are many shades of opinion on all this, and no monopoly on what the right answers are.
  • wizzo227's Avatar
    Level 13
    Lets not go off-topic for this thread.
    Yesterday after my walk around the block in the drizzle, the living room still felt a bit chilly and thermometer showed 17.8C, so HEAT PUMP ON.
    That got it nice and warm, using 0.55kWh of mostly bought electricity and probably gathering about 1.5kWh of heat into living room air.
    That morning I had also used a further 6kWh in the gas boiler, sending that heat to whole house as well as a bath.

    Conclusion: 2kW(peak) of photovoltaics plus a 2kW(thermal) heat pump is Insufficient for a well run home to live at genuine nil net zero (CO2). More renewables are needed.
    Too much dependency on the honesty of energy suppliers of "100% renewable" is (I allege) incompatible with a survivable future climate, which is partly why I use less and don't give money to them unnecessarily. Since September last year, my electricity bills for genuine metered usage have been consistently less than the government £66 per month giveaway, so I haven't paid them a penny. Not a penny.
  • meldrewreborn's Avatar
    Level 81
    @AndyThornton

    Governments seem to want us to decarbonise by banning fossil fuel using devices.
    the public instinctively doesn’t like being forced in this manner. But the public accepts pricing adjustments - think alcohol, tobacco , road fuels, sugar etc.

    I think extra tax on domestic gas (fully offset by tax cuts elsewhere) would let people decide for themselves how to heat their homes.