water scource heat pump

[regen]

'There are DX heatpumps that transfer  heat directly from a source i.e. copper pipes  that are part of the heat pump circuit  go into the ground or water.   It  obviously  cannot be used in a well  if the water is used for drinking and the  refrigerant is toxic  but that is what is normally known as a direct system.'

Thanks DHaslam - Looks like I am still learning.  I will be using the overflow from the well and this could be brought a lot closer to the house and fed into a large under ground tank which would then overflow continuously to 'Waste' at rates between 0.5 and 7.5 lps.  Do these direct systems achieve the same COP as a straight through system in like for like situations?  I also understand that the dimplex can tolerate a poorer water quality than most water heat pumps but assume that the use of a copper coil would mean neutral ph low disolved oxygen etc.

Regen

[knighty]

how big will the tank be ?  the bigger the better....

that way when the heat pump isn't running the tank should warm up a bit and act as a low temp heat store

remember to plumb the overflow in so the overflow water is coming from the bottom too :-)

[regen]

Thanks Knighty,

Project still in very early days. (I would really like to put in a high head hydro but have been dithering due to the cost of MCS installations vs my available water supply which would generate a max of 13000kwh pa but would need about 70% efficiency for this.  According to companies who could install for a price this is achievable but info form this forum inicates this may not be possible in the real world!)

Currently putting in 300l thermal store to combine wood and oil boilers with potential to feed in surplus electricity from PV - Hydro would fit in to this system but not sure that the water heat pump would be a major benefit.

Regen

[ecogeorge]

Thanks Knighty,

Project still in very early days. (I would really like to put in a high head hydro but have been dithering due to the cost of MCS installations vs my available water supply which would generate a max of 13000kwh pa but would need about 70% efficiency for this.  According to companies who could install for a price this is achievable but info form this forum inicates this may not be possible in the real world!)

Currently putting in 300l thermal store to combine wood and oil boilers with potential to feed in surplus electricity from PV - Hydro would fit in to this system but not sure that the water heat pump would be a major benefit.

Regen

You've got 13,000 kWh available 
That's 35kWh / day or a 1.5kw electric fire  running 24/7 !!!!!!!!
Get on with the hydro man , the heat pump will wait.
just my 2p.

[clockmanFR]

regen,
Get digging, get that hydro planned.
We have a small stream here good flow but only 0.5m head, so its just not economical.

But 1.5kw per hour, that sounds financial feesable, that's if you don't get the contractors in at labour charge £1500 per week per man.

Give the hydro section on this forum a tinkle, theres some wise old sages, with realistic points of view.

If you were closer even i would get my spade out + design skills, and come and help you, (i only require watering). 

[knighty]

^^^ what they said

hydro, connected directly to a small immersion heater in the bottom of your thermal store will be ten times better than your heat pump

and if you need more heat, you can always top the thermal store up overnight on E7

the hydro will work out much cheaper/better than running your heat pump

can you fit a bigger thermal store ?  the bigger the better tbh
(probably 1000litres ish?)


assuming if you were considering a heat pump you're thinking of underfloor heating ?

if you post up a rough layout/size of the house the guys on here who deal with thermal stores should be able to give you a rough idea of what you need :-)

[A.L.]

hello,

but have been dithering due to the cost of MCS installations vs my available water supply

You may not be aware that until at least 31/03/2012 micro-hydro will be handled under the ROO-FIT process and would not appear to require any MCS involvement. This time period has already been extended from Sept 2011 and may be extended again, keep an eye on Phase 2 of the current 'review'.

www.mypoweruk.com/FIT-Generator-Guidance_V2_final18.10.11.pdf

[regen]

Hi A.L

Thanks for the link.  What exactly does it mean in practical terms?  My understanding was that the hydro turbine and control gear had to be on the Fit approved list together with the installer but the choice was very limited. How does the Roo fit change this?

Regen

[regen]

Ecogeorge, clockman, knighty,

Thanks for the encouragement.  Wish it was that simple - I would have it in by now. 

The sums do not add up if i go for installation with out FIT - potential annual saving on leccy bill of around £300 and a about £200 max on heating bill as most heating is from own wood supply.  Reckon planning and permissions at about £1500 pipework at £2000, intake £500, turbine with spear valve £5000, turbine house £500 , cable £1000, and electrical commissioning £1000 - Total £11,500 - pay back around 20 years at todays electric prices.

With FIT it is more realistic

Due to probable constraint imposed by DNO max hydro would be 2.2 kw which in the last 12months (sept 10/aug 11) would have generated 9108 kwh based on my daily water flow readings, a 60 m head corrected to 57m to allow for 95% efficiency on a 300m pipe with a 99.4mm ID taking a max of 6.0 lps. The size of turbine is also determined by the need to maximise production during low flow periods.-

However the utilization based on my flow readings came out at 59.2% indicating a total annual production of 11409 kwh so the answer is probably between these 2 figures.

Taking the lower figure the annual savings/ Fit payments would realise around £ 2560 but quotes to date have been in excess of £28000 -payback minimum 11 to 12 years.

So i am still looking for an installer who can supply and commission the hydrogenerator and electical connections to FIT standards for a reasonable price.

Regen

[A.L.]

hello again,

from page 12 of the linked document,

2.3. For the purposes of ROO-FIT accreditation, an eligible installation is an installation that does not use an MCS-FIT technology and would receive accreditation under the ROO, were an application to be made for such an accreditation4. As part of changes to the FIT scheme in May 2011 and August 2011, hydro installations with a DNC of 50kW or less that commission prior to 31 March 2012 are also eligible to seek accreditation using the ROO-FIT accreditation process.
2

I interpret this as meaning that any otherwise legal (planning permission etc) system could get the FIT tariff, suggest you speak to Ofgems renewables team if necessary.

also look a 8th Nov story here - microhydroassociation.co.uk/default.aspx

maybe pm guydewdney on here as he has practical experience I believe