Heat Pumps, One for the engineers

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NewcastleFalcon
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Re: Heat Pumps, One for the engineers

Post by NewcastleFalcon »

..and lo and behold we are onto page 3. I would say front running will be air-source heat pumps/ better insulation/draught proofing windows for existing dwellings. Perfectly possible to build new homes which require very little heating.

Bit about water source heat pumps here. Not very widely applicable I would think, but still covered in some of the schemes eligible for assistance.

https://energysavingtrust.org.uk/could- ... -work-you/

Regards Neil

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Re: Heat Pumps, One for the engineers

Post by Dormouse »

Just hot tap their electricity supply while you are at it. They might never notice. And if they do, just say your Smart Meter told you to do it.

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Re: Heat Pumps, One for the engineers

Post by Gibbo2286 »

myglaren wrote:
01 May 2021, 14:02
I wonder if it would be cost-effective if I were to breach the wall to next door and suck the heat out of their house?
Do you think they would notice?
I had a mate who dabbled for a while in property, he bought a large cottage and split it into three units, the two outer units sold quite quickly so he was then stuck with the middle one which had no water supply, when one of the new owners went away for the weekend he broke through the wall and connected the middle house to the mains under the bath. :shock:

I often wonder if it's ever been discovered.

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Re: Heat Pumps, One for the engineers

Post by xantia_v6 »

The subject of heat pump efficincy is a bit confusing t the uninitiated. Here is a graph of typical performance for an air to water heat pump. Each line represents a different outlet temperature.
The advantage of a groud-source system is that (if correctly installed) the inlet temperature is always above freezing.

Image

In the case of our heating system, the outlet temperature will be 25 - 30 degrees, and the ambient is (almost) never below freezing, so I am expecting a COP of about 4 (400% 'efficiency').

Air to water heat pumps are not well suited to running conventional radiators, because of the higher outlet temperatures required.

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NewcastleFalcon
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Re: Heat Pumps, One for the engineers

Post by NewcastleFalcon »

Bit of visuals from wiki
A: indoor compartment, B: outdoor compartment, I: insulation, 1: condenser, 2: expansion valve, 3: evaporator, 4: compressor
Image
https://commons.wikimedia.org/wiki/File ... -cycle.svg
Original source file: User:Ilmari KaronenKeno at en.wikipedia.
and animation from the Energy Saving Trust


Yes I'm sure those clever people at Mitsubishi, and elsewhere can knock together the gubbins required a bit cheaper than they currently do.

Regards Neil

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mickthemaverick
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Re: Heat Pumps, One for the engineers

Post by mickthemaverick »

Anyone tried installing chest freezers on the patio with the evaporators up against a house wall with an air brick or two to take the heat inside? Also means you have somewhere to keep the BBQ ingredients!! :?: :-D

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Re: Heat Pumps, One for the engineers

Post by Gibbo2286 »

My experience of chest freezers comes from running the shop, we had two large ones, they were damned expensive to run and suffered frequently with the cooling fins getting blocked by dust.

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Re: Heat Pumps, One for the engineers

Post by NewcastleFalcon »

This is a more in depth video it lasts a whole 9 minutes 42 seconds but covers all the different types with nice animation. I found it very informative.




Regards Neil

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Re: Heat Pumps, One for the engineers

Post by mickthemaverick »

Curiousity compels me to ask Gibbo, were they the display type with see through lids? Our chest in the leanto seemed a lot more economical than the old upright which lost its cold air everytime you opened the door in our cosy kitchen. The combination of siting it in a cooler place and having a decent top lid meaning the cold air stayed inside when you opened it made it much cheaper to run. As it was the exhaust heat was going through a drier from an old LDV refiigerated van into the shed and keeping that above freezing point in the coldest of days. A good setup maximising the use of the power but in the end we didn't have enough use for a big chest so we have reverted back to an under counter upright and suffer the extra cost for the convenience benefit!! :)

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Re: Heat Pumps, One for the engineers

Post by moizeau »

Geotherme is popular here if you're building a new house. In the countryside a small garden is 1000m2 so size isn't an issue. It's a lattice of pipes about 1m under the ground covering about 40m2 I think. A gel is pumped through the network and then the heat extracted. He told me for 4kw of heat it costs 1kw of electricity. It's all underfloor, OK with a new build, and cost about £15k all in, again, in a new build it can be budgeted in. The house remains the same temperature all year round and he gains space in each room because he hasn't got any rads.

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Re: Heat Pumps, One for the engineers

Post by myglaren »

We had a large chest-freezer in the 'utility' room and another upright in the kitchen. Wife's idea.
We used to buy meat in bulk - a lamb, half a pig, half a 'beast' (cow).
Initially expensive but she would portion it out and freeze most of it. Spend the weekend cooking and baking and freeze a fair bit of that too.
Didn't need to do much shopping, only fresh veg, butter, eggs etc. There was enough food to survive for ages but the main thing was the baby dinners for the small ones.
She was wary of commercial baby food, partly due to preservatives and E-numbers that were heavily criticised at the time, and also some nuts going around contaminating baby food - broken glass etc.
She knew exactly what was in her baby meals and was happier with that.
Not least was the savings on food, bulk buying meat was actually far cheaper than buying it piecemeal.

The freezer kept that room reasonably warm in winter and her cooking non stop over the weekend kept the rest of the house warm too - she insisted on a slow-cooker double oven that ran all night too.
Which reduced the heating bills and also the gas bills as there were many items being cooked at the same time. Hard work for her but she revelled in it and there was always fresh bread and cakes, no need to buy any.
Smart woman. Learned a lot from her.

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Re: Heat Pumps, One for the engineers

Post by NewcastleFalcon »

So what's the stuff that courses through the pipework, valves compressors and heat exchangers.

This stuff with its useful physical properties, part of this informative vid here. link
temp2.png
What's the bets the pink stuff is more expensive than the green stuff :?: :-D

These Hydroflourocarbons (HFC) are in worldwide use in refrigeration, air-conditioning and if the scaling up away from gas happens, in heat-pumps on a massively large scale than at present.

In themselves HFC's replaced the Chlorofluorocarbons (CFC's) well-known and banned for their environmental impact on the ozone layer.
From wiki https://en.wikipedia.org/wiki/Hydrofluorocarbon
They do not harm the ozone layer as much as the compounds they replace, but they do contribute to global warming, with trifluoromethane having 11,700 times the warming potential of carbon dioxide.[
Regards Neil
Last edited by NewcastleFalcon on 02 May 2021, 13:07, edited 1 time in total.

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bobins
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Re: Heat Pumps, One for the engineers

Post by bobins »

R744 can be used as a refrigerant gas as well - commonly known as Carbon Dioxide. One of its drawbacks is that it needs a significantly higher pressure to work at.

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Re: Heat Pumps, One for the engineers

Post by Dormouse »

NewcastleFalcon wrote:
02 May 2021, 09:59
Bit of visuals from wiki
A: indoor compartment, B: outdoor compartment, I: insulation, 1: condenser, 2: expansion valve, 3: evaporator, 4: compressor
Image
https://commons.wikimedia.org/wiki/File ... -cycle.svg
Original source file: User:Ilmari KaronenKeno at en.wikipedia.
and animation from the Energy Saving Trust


Yes I'm sure those clever people at Mitsubishi, and elsewhere can knock together the gubbins required a bit cheaper than they currently do.

Regards Neil
In this set of diagrams I wish they would use a pale green/blue for the ambient air temperature comparison to the darker blue of the colder return after the expansion phase. Most people can't get their head around taking heat from "cold" - the outflow temperature is lower than the outside ambient temperature and hence you can take heat from the "cold" outside.

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Re: Heat Pumps, One for the engineers

Post by Gibbo2286 »

mickthemaverick wrote:
02 May 2021, 10:59
Curiousity compels me to ask Gibbo, were they the display type with see through lids? Our chest in the leanto seemed a lot more economical than the old upright which lost its cold air everytime you opened the door in our cosy kitchen. The combination of siting it in a cooler place and having a decent top lid meaning the cold air stayed inside when you opened it made it much cheaper to run. As it was the exhaust heat was going through a drier from an old LDV refiigerated van into the shed and keeping that above freezing point in the coldest of days. A good setup maximising the use of the power but in the end we didn't have enough use for a big chest so we have reverted back to an under counter upright and suffer the extra cost for the convenience benefit!! :)
They were open top for self serve Mick with only an aluminium lid for when the shop was closed, the see through tops came later as everyone wised up to the need to cost cut.