Could I just ask the experts about heatpumps?
I have a feeling that my heatpumps are the reason for my exorbitant electricity bill. If they haven't been serviced for some time could they be running extra inefficiently?
I only want to heat my water tank to around 30 degrees and I would have thought for such beasties that wouldn't be too taxing.
Any suggestions welcome.

Ste.

Can you tell me about your heatpumps, are they air source or ground source and how large is your tank?

Regards, Dave

Try this one for an example of what solar power can do near Seville.

http://www.engadget.com/2007/05/04/s...n-entire-city/

Jim

They haveb been using vacuum tube solar systems to heat oil to 400°C the oil then heats a water boiler, producing steam which then drives a turbine producing electricity.
The domestic vacuum tube systems are generally limited in their output but will if left to their own devices produce steam.

Regards, Dave

That is interesting, I couldn`t get the video to work though.

Thanks for the link Jim......amazing

Dont think i would of climbed up that tower though.....to near the reciever

ATB

Hi Dave,
Air source heat pumps, one has been offline for a bit as it keeps tripping, but surely two is overkill?
I don't know the volume of water but the tank is about 1.8m tall and probably 700mm ish in diameter, so that would be about 2000L wouldn't it?

I enclose some pics from the 'engine' room'.

(The pumps are also near a set of tilting patio doors so they get airflow)

Thanks for the input!

Ste.

Thanks Splatt,
I am a little lost what those two are doing for you, I could not imagine them being used just to heat 2,000 litres of water I would see them as heating a very large pool.

Looking at them I'd expect about 30kw of heat output but as they are inside don't they freeze the inside room, I assume that they have a fan that draws air up and out through the ducts?

Normally air source heatpumps are installed outside as they require to drag large volumes of air through the system and directly outside, I could imagine your duct could induce a back pressure reducing efficiency.

Do they really just heat that tank??

Regards, Dave

Is there no back to grid sytem in place in spain?
I sell solar panels in Australia and the whole idea is to feed the grid when your not using the electricity it generates and get paid for what you dont use.
There is a government grant here of approx 4000 euros and for a 1kw system it is an out of pocket exspense of around 1000 euros.
I would think spain will do somthing similar in the future.
Great idea

Not as yet for private individual systems although there are of course a lot of commercial solar farms popping up everywhere.
The majority of private PV installations on domestic properties here happen simply because there is no choice i.e. there is no chance of connecting to the grid in the first place (unless you fork out thousands for a new substaion, pylons etc), never mind contributing to it.

Would be a great idea, the insentives are excellent here.
Unfortunaltley a lot of the aussies are very sceptical.

I am sure you can get incentives in Spain to sell back to the grid but of course you need to have a grid connection in the first place.

I feel sure a friend of mine was saying a PV system installed was about 15,000 Euros for 15kw.
I am not 100% sure but I will ask when I next see him.

Regards, Dave

Hi Dave,
There are some large patio doors 5m away from the pumps so they do get some air, you can feel the draught when they're on, and yes it is sometimes possible to see ice building up on the blades of the grills on the pumps.

The system can also feed water to the pool, but apparently that hasn't been switched on for 9 years! There was also the option to supply hot and cold water to fan coils in the living and bedrooms. This was supposed to be a heating/air conditioning system but to me it seemed rubbish so I removed the fan coils. They were huge ugly boxes in the rooms.

Thanks,
Ste.

looking at your cylinder measurments I would guess it is more like 400/500ltrs( and probably less) than 2,000l, (http://www.online-calculators.co.uk/volumetric/)if you take into account insulation etc call it .35m x 1.5m , the heatpumps look pretty big for just that tank( and the 30kW is really excessive just for hotwater), and now you say you have taken out units in other rooms, I would now suggest the whole system is out of balance, and that the cost of running just the pumps for hotwater is totally out of proportion to the amount of heat produced, it also looks like there is a very big ducting system above the pumps, does that go external or to a ducted air system. If you have already removed the heating cooling exchangers in the rooms, I would take the heatpumps out and put in a couple of Solar panels(on that volume of water I would guess you need 3 or more) and connect to the existing tank and support with an immersion heater for winter. (unless you are going to get the system working properly on heating the pool!!) your hotwater running costs would drop dramatically. and would be FOC from about Apr thru to Oct. with much less, benefit being gained during Nov Dec Jan Feb,

On the subject of selling back to the grid, There are no direct incentives, but once installed the sell rate is now about 24 to 26€cents, per KWH, about 2.5 times the buy rate(used to be 42€cents which made it a very good investment), Should you wish to put in a sell back system to offset cost of domestic usage you would need about a 15KWp per day system, which would be higher than previously stated(I would say 18 to 22K€) than above when you take into account all the associated charges with Permissions, Boletins, connection to grid etc also note that it would have to be a seperate connection as the principle of credit and reversing meters is not accepted in Spain, however this all really depends on location, access to grid and local conditions to a great degree.

Hi Whizz, yes the ducting is routed to the outside.
To further complicate matters I also have two large immersion heaters for hot water, the largest of which is switched off as we just don't need all that hot water.
I was also thinking that the hot water tank connected to the heatpumps was in addition to the water that was in the pipes under the floor. I don't know how densely they are fitted or what bore the pipes are, but in total I guess there is 300m2 of coverage upstairs with a further 100m2 or so in the downstairs apartment so that must be a fair bit of water.
I would love to have the pool heated, and all pumps and pipework are in place, but it is the expense.

Any idea how much I could sell two heatpumps for?
To go solar would be ideal, I just don't have the money right now so it's a case of damage limitation and wear more jumpers.

Thanks
Ste.

(Take this thread to Cuba!)