Solar Thermal Energy (warm Water)

[martincvs]

I am considering installing a solar energy system to produce hot/warm water. Total cost incl installation is 70,000 Baht. According to the information I received, payback is in about 8-10 years, with a saving of 8000 Baht per month (2MHh per year saved).

Payback period still seems long, not sure about maintenance and repair costs.

Would welcome views/suggestions.

[katabeachbum]

I am considering installing a solar energy system to produce hot/warm water. Total cost incl installation is 70,000 Baht. According to the information I received, payback is in about 8-10 years, with a saving of 8000 Baht per month (2MHh per year saved).

Payback period still seems long, not sure about maintenance and repair costs.

Would welcome views/suggestions.

I did some calculations 2 years ago, and ended up with a 200 litres boiler from Fagor at 20.000 baht. I have a separate meter to the boiler (at 400 baht) just out of curiosity, and electric consumption is very low, 1-5 units a day (4-20 baht). Temp on cold water inn is 25-30 degrees and hotwater is 80 degrees. Tank on the roof where it is 25-35 degrees in the air. 6 bedroom house.

Should be maintanance free for at least 10-15 years even in LOS, my experience back home is hasslefree boilers for 15-20 years.

And always hot water, even if raining for a week

[InterestedObserver]

You will have to take an awful lot of very hot showers to use "2MHh" [sic] of energy yearly. Is this installation for a guesthouse?

[Crossy]

You will have to take an awful lot of very hot showers to use "2MHh" [sic] of energy yearly. Is this installation for a guesthouse?

If he's expecting to SAVE 8,000 Baht a month on water heating it's got to be a hotel, with 8-10 years payback of 70,000 it's likely 800 Baht a month saving on water heating.

Solar works very well here, our neighbour has 3m² of panels which he says gets the water too hot, a bit coy about the cost though (thinks he got taken )

[InterestedObserver]

Solar panels are expensive per KWh. You have to do a lot of creative number crunching to justify their use, whether it be for electricity or hot water. A business model with an 8-10 year payback period is not exactly first rate. Installations in the real world almost always come with subsidies of some kind or another to help offset the cost.

[jaapfries]

I am considering installing a solar energy system to produce hot/warm water. Total cost incl installation is 70,000 Baht. According to the information I received, payback is in about 8-10 years, with a saving of 8000 Baht per month (2MHh per year saved).

Payback period still seems long, not sure about maintenance and repair costs.

Would welcome views/suggestions.

HiMartinCVS; I don't know where you get your Bt. 8000.- savings-per-month from, but that depends on how much hot water one uses, obviously.

The avarage person uses about 160 Liters of hot water per day. That is water at a (mixed) temp. of about 40 degrees C.

The avarage 4 pax family in an avarage 3 bedroom home will spend approx. 25~35% of their overall Power-Bill on Hot Water (similar to the outgoings for Airconditiong, by the way).

A good basic, but well constructed Solar Hot Water System (with immersion-heater) should cost you about Bt. 50~60 K in Baht and would be sufficient to service that avarage home as described above.

Of course, if there are bathtubs in every bathroom AND people using these on a daily basis, things will be vastly different.

Another thing is that "ugly tank" on the roof; this is not necessary, since this tank (without the need foor a SS mantle = save money !) can also be installed under the roof in the attick space, as long as it is positioned HIGHER than the solar-collector-panel(s) which is/are on top of the roof and preferably facing South.

ROI (Payback) would be about 5~7 years, but mor importantly; your household would contribute to the environment by a reduction of some 2 metric tons of CO2 per year ! !

If you are interested in a system like this, drop me a PM and I will put you in touch with a European Engineered and manufactured system, 'made-in-Thailand'

Cheers,

JGK/Pattaya

[Gary A]

I'd have to say that 70,000 baht is a lot of money for a passive hot water system. There is also a huge difference between solar electric and passive solar. I can't imagine anyone wanting a solar electric water heater. I'm sure that the hot water shower unit I have costs no more than 500 baht per month to run.

I lived in an apartment that has a passive solar system on the roof. I ended up having to do some more plumbing to add a cold water supply because without a mixer the water was TOO hot.