theoretical discussion Heat pump for cooling?

[GreatCamel]

I have been seeing a lot of talk online lately about making a shift from traditional heating like gas furnaces and water heaters,

to using heat pumps to save on fossil fuels.

 

My random thought of the day came while doing some touching up on HTML, and got me thinking about servers.

I know there has been a big growth in water cooling across the board in computers. Now if you wanted to run a decent sized

home rack server, could someone use a heat pump to not only cool their set up but also tie the "exhaust" heat into the heating

solutions of their home?

 

I know its not as simple as just plugging a couple hoses in and off you go, it would defiantly take some engineering in order to

make a bypass from your heating system to the outdoors to prevent overheating other components of you house, and unless 

you are running something really beefy and hot as a server it probably wouldnt be enough to heat a house on it's own.

 

In a day where efficiency is everything, this has been my random thought for the day.

 

-Great Camel 

[Fasauceome]

On a basic level, I have gotten into the habit of firing up F@H and letting my GPU heat up my room so conceptually it's totally doable.

[tkitch]

A Single PC can't heat a house.  Even an 800W PC wouldn't be enough for even a small apartment.

Could it help?  Sure.  All you'd really need is a ventilation fan to remove warm air from the PC's room into a room you want more heat in.  

[CT854]

You could theoretically construct a distributed system where you set up radiators to exhaust heat generated from load-heavy tasks (mining, F@H) across multiple GPUs/misc. heat generating devices. However, doing it at this scale would probably be more of a reliability issue than anything else, since you have to worry about the many potential points of failure and depending on the implementation it may be hard to troubleshoot.

 

I feel like the only real practical scale this could be implemented on is, as others have pointed out, on the scale of a single room.

[Zomeguy]

In the room I have my PC it's temp is usually 2-4 degrees C higher than the rest of the house (small room only like 100 ft sq). In winter it's great, in summer not so much.

[AnonymousGuy]

I don't understand the question.

 

Can you use waste heat to heat your home?

 

Uh....yeah...obviously.  Heating an entire home though of average size is typically done with the equivalent of 20kW....way beyond what anyone is doing with computers.

 

 

[GreatCamel]

this was more a question of making the particular tech mesh up more than "is it possible to use a computer as a space heater.", there is obviously a lot about how a lot of modern builds making a lot of heat.

 

As i stated in the OP this idea is less for a small (comparatively) PC and more in the case of running a personal server at home that is likely to be putting out a higher maintained heat output (obviously depending on the use case) making it move viable to a larger scale than trying to heat your house with a single PC.

[thrasher_565]

you can make an off grid house headed for free... just you cant build it is the problem.. because of laws... house are extremely inefficient and are designed to fall down.

 

there is zero design for earthquakes or tornadoes witch destroys most houses.

[Demonic Donut]

On 6/1/2022 at 3:05 PM, Caroline said:

In theory. But what you don't spend in your gas bill you spend it on insulation and sealings as rooms heated by pumps have to be hermetically sealed in order for it to work as intended, if cold air gets inside it'll instantly create an inbalance and force the pump to be constantly on or rapidly cycling through on/off states thus wasting power.

It's the promise you'll save by spending -in some cases- huge amounts of money first.

 

In order to make electric heating *actually* more efficient than burning gas, coal or other fossil fuel the power should have to be generated by a nuclear reaction or a hydroelectric plant of ludicrous dimensions.

 

Otherwise your fancy electric heater feeds off power that comes from burning fossil fuels, if I go right now and plug a space heater 100% of the power it uses will be generated by burning coal at the local power plant, there only 20% of the heat obtained by burning that coal will be useful to generate power, the rest is wasted so... it's a terrible way to generate power but the raw amounts of coal available outweigh that problem.

But, if I head downstairs and fire up the boiler then 80% of the heat made by directly burning gas will be converted to heat that goes into the rooms via radiators, the rest is wasted in the boiler acting as a huge heatsink, some of the steam escaping eventually escaping through pressure relief valves and the pipes and walls also soaking up part of the heat as the steam moves through them (transmission loss).

 

What does all of that have to do with heating a room using a server? I have no idea but probably everything, discuss.

Regarding heat pumps and gas boilers/furnaces, this isn't 100% true.

 

Insulation and sealing apply just as much for a hydronic loop, gas furnace or heat pump. Assuming ductwork is sealed properly, there isn't going to be a big difference in heat sources with a house that is similarly sealed/insulated. Convection will suck the heat out of any house.

 

All will cycle, all will experience energy loss from cycling. But a heatpump suffers more from cycling, mainly due to electric motors high starting current and time to stabalize pressures and temperatures.

 

Furnaces and boilers lose their efficiency from flu gas, not so much from the boiler being a heatsink. As long as the boiler or furnace is in the conditioned space, there isn't any heat loss from the boiler itself. Its the 300 degree exhaust going outside. Thats why all high efficiency boilers and furnaces are condensing units that drop the flu gases below condensing temps, removing more sensible and latent heat from the combustion air.

 

A variable rate boiler, furnace or heatpump avoid this to some extent by having a good turndown ratio. Being able to limit their output to a fraction of their full output to load match. Newer inverter driven heatpumps are incredibly efficient and will run at a fraction of their output to maintain setpoint instead of cycling. Inverter units can achieve 4:1 turndown, but many boilers can go as far as 10:1 which is quite impressive.

 

Depending on your energy source, a gas furnace or boiler could be better for the environment. But residential equipment is not held to the same maintenance standards as commercial or industrial equipment. Its not just CO2 output, but CO and NOx, which is quite important as it causes things like acid rain. These are tightly monitored and restricted in the commercial and industrial sectors. A proper tune can reduce CO2 output by 10%, halve CO and reduce NOx considerably as well. And these are conservative numbers.

 

Out of curiosity I did some math.

 

Coal is the worst CO2 producer at 2257 pounds per MWh while natural gas is at 977 pounds per MWh.

 

A therm of natural gas produces an average 11.7lbs of CO2 for an average consumer. If we assume 80% efficiency, that's 80,000BTUs per therm.

 

Math time. I'll just use the MWh amount of power.

 

2257lbs of CO2 per MWh from coal, furnace equivalent would be 15,432,479 BTUs rounded up to the nearest BTU.

 

977lbs of CO2 per MWh from NG, furnace equivalent would be 6,680,342 BTUs rounded up to the nearest BTU.

 

So now the heatpump. To make it easy and sway in favor of the furnace and the dirtiest power producer, I'm just going to use the larger BTU amount of the coal plant electrical vs natural gas furnace.

 

The easiest math will be to decide what HSPF (Heating Season Performance Factor) we need to achieve in order to beat the gas furnace.

15,432,479 BTUs / 1000 / 1,000 KWh = a HSPF of 15.43.

 

Well that doesn't look good. Coal is dirty! Furnace/boiler wins hands down. Let's try the NG power plant.

 

 6,680,342 BTUs / 1000 / 1,000 KWh = a HSPF of 6.68.

 

Thats much better and actually attainable by all modern equipment. High efficiency heatpumps are usually considered HSPF of 8 or better. And in my area you cant even buy a new unit with lower than 14 SEER efficiency, which generally range from 8-9.5 HSPF.

 

So depending on where your power is coming from, a heatpump may or may not be better for the environment. For my area, coal is less than 25% of power produced, 35% hydro/solar/wind. So a heatpump is a better option by far in my area.

 

There are also high efficiency furnaces and boilers, achieving 90%, 95%, or even 98.5% efficiency. Although those numbers are under some very whiteboard perfect variable scenarios, although so are the heatpump numbers. So it's a moot point.

 

The biggest problem, in my opinion, as a consumer is cost. A high efficiency unit sounds great. A heatpump replacing a gas furnace is a great environmental choice.  But they are expensive. I crunched the numbers when I installed AC, debating going with a heatpump when my natural gas furnace works just fine. The ROI was 4-7 years depending on runtime. And that's with me purchasing the equipment at wholesale and installing it myself, AC only vs a heatpump unit of the same efficiency. And the higher efficiency ones had an even longer ROI. A condensing furnace is thousands of dollars. High efficiency heatpumps are as well. People need incentives to do this, and the $700 tax break in my area is not nearly enough.

 

Anyway, thats my rant.