Heating idea, wondering if it's worth it.

Squeeb_2

Hi all.

I bought a portable airconditioner unit during the hot summer so that I could cool my bedroom down during the ridiculously hot nights.

I would put the exhaust duct out of the window and block up the gaps with pillows etc. to prevent the hot air from coming back in.
This worked beautifully.
I did notice that the hot air being removed from the room was like a hairdryer.

Now for winter:
I have a small room (about the size of a broom cupboard) with a couple of computers in there that are on all the time.
As you can imagine the ambient temperature in there remains quite high when the doors are closed.

My idea is to put the airconditioner inside the cupboard and vent the hot air out of the cupboard and into the open space of the house.

I have already worked out the risks of pumping additional humidity into the open space and have concluded that the air is dry as the condensing method of the airconditioner also acts as a de-humidifier, the excess water is stored in an internal tank.

The airconditioner will not be on constantly and will only cut in when the temperature rises above an average of 23 degrees C until the temperature is below the threshold of 21 degrees, then the unit shuts off and waits for the ambient temperature of the cupboard to rise again.

So far, it does this roughly every half an hour and stays on on for approx 15 mins.

My question is:

Is this method going to be cheaper than turning on my combi-boiler central heating. The hot air being pumped into the open space appears to provide ample heat and the house is insulated enough that it lasts for a while.

My theory is that the combi boiler uses both electricity and gas to produce heat whereas the aircon method only uses electricity.

However, I am rubbish with figures so I would love to know if what I am doing is saving any money at all or am I barking up the wrong tree.

Regards,
Squeeb

macman

Might be cheaper just to open the cupboard doors and let the heat escape...
A kWh of gas is 3.5p, a kWh of electricity is around 10p.
Your combi uses a minimal amount of electricity to power the pump, circuit board and timer. Probably less than you are wasting by leaving 2 PC's on 24/7.

fred7777

Squeeb wrote: »

My theory is that the combi boiler uses both electricity and gas to produce heat whereas the aircon method only uses electricity.

Your theory is wrong. The combi boiler uses only a small amount of electricty and as gas prices are cheaper than electricity prices the boiler will be cheaper.

moonrakerz

It would be even cheaper to leave the door open ................

rogerblack

It would indeed be cheaper to leave the door open - however.
Portable air conditioners can be moderately efficient - pumping 2.5kW of heat, for each 1kW input.
If you have the air conditioner in the 'hot' side - this rises to 3.5kW.
If you can find a source of 15C air, for example, and the air conditioner is happy to work to 'cool' this environment, then you can move this heat into the heated space very efficiently.
One caveat.
If you cool a room adjacent to another room, you will increase heat going through the wall.

DirectDebacle

Might be cheaper to turn the heat to the house off and live in the computer cupboard.;)

Pincher

Put a vent grille on top, vent grill at the bottom. You should get some natural rising heat circulation.

You are trying to recycle the waste heat, not use more energy.

lcharm

I did notice that the hot air being removed from the room was like a hairdryer.

That's not the heat being removed from your room, that's the heat generated by the aircon compressor working which needs to be vented otherwise it cancels out the effect of the cooling system!

The process you propose is very wasteful because you are employing a 3-4KW system, which is purposely designed for cooling, and use it's secondary byproduct, HEAT, which is not at the same temperature levels of what a designated heater is designed to produce and the heater will heat a room with less effort.

victor2

Pincher wrote: »

Put a vent grille on top, vent grill at the bottom. You should get some natural rising heat circulation.

You are trying to recycle the waste heat, not use more energy.

Add a fan if you want, to blow the warm air out of the top vent.
But as already said, opening the cupboard door will allow the air to circulate and won't cost much.

Squeeb_2

Hi guys, thanks for the advise. I'll invest in putting some slat vents in the cupboard door at the top and bottom to get some natural air flow going.

The computers are staying on I'm afraid, they run my home automation, CCTV, media distribution (gotta have my man-den) and backups from the macs in the studio :P

The main server has a 400W PSU although I doubt it constantly pulls that much (advise?)
The other system is an old PowerBook g4 acting as my router, it draws 65W max although while it's not charging I also don't think it's pulling the full 65W.
Neither system has a display running.

Just deffo want to make use of that heat.
Unfortunately, simply leaving the doors open doesn't appear to provide much heat at all to the open space however inside the cupboard itself (about a meter In depth by two meters wide) is toasty. The open space outside it is cold.

Just need to find the best way of shifting that heat out of there as efficiently as possible.

victor2

Just get one of those plug-in power monitors (less than a tenner on fleabay) and put it on the main plug feeding everything (the supply to a UPS perhaps?)
Then see what it uses over a normal 24 hour period and you'll have your energy usage for your cupboard.