Air Con/hot Water Units

[sbk]

My husband picked up a brochure from buddy air (buddyair.com) about an ac unit that also produces hot water. The claim for a 9000 BTU unit is that it consumes about 4800 baht a year in electricity.

Anyone ever try one of these units? Do they really work?

Heres the pic from their site:

[jasreeve17]

I'd be interested in this too, SBK.

I haven't seen that buddy unit before, I'll be checking this thread for any good advice that comes in.

I was going to buy a Mitsubishi aircon for about 20k (a 25 sqM living room) and an AIG hot shower unit for about 5k. Any thoughts? I've just got my homepro credit card so money is no limitation... or that's what the missus thinks.

(My current LG aircon is quite noisy.)

[Crossy]

Well they definately work, stayed in resort in Malaysia a few years back, instructions in the bathroom 'turn on aircon for hot water', about 30 mins of aircon was more than enough for a shower for two

It'll be interesting to work out the break even point for price/running cost comparison between one of these and a conventional aircon + water heater.

I'm certainly interested in thse units, with solar for a pre-heat I don't think we'll need a conventional water heater.

[Tyke]

The quoted cost of hot water for the shower is probably over and above the cost of running the air conditioning, which is probably relatively expensive overall as the hot water has to travel from the unit to the shower in the bathrrom - way inefficient. You probably only save money on the intial cost of the unit but that is small compared to the cost over the lifetime of the unit.

It doesn't seem convenient or cheap to run the air conditioning for 30 minutes. as one poster wrote, to get a shower for 2 - sounds like camping or caravanning to me. In any case I very seldom use air conditioning so for people like me it would be rather unsuitable. Plz let me know if u come across ceiling fans that can generate hot water or toasters that can flush the loo and I will perk up.

[Erwin1011]

The quoted cost of hot water for the shower is probably over and above the cost of running the air conditioning, which is probably relatively expensive overall as the hot water has to travel from the unit to the shower in the bathrrom - way inefficient. You probably only save money on the intial cost of the unit but that is small compared to the cost over the lifetime of the unit.

It doesn't seem convenient or cheap to run the air conditioning for 30 minutes. as one poster wrote, to get a shower for 2 - sounds like camping or caravanning to me. In any case I very seldom use air conditioning so for people like me it would be rather unsuitable. Plz let me know if u come across ceiling fans that can generate hot water or toasters that can flush the loo and I will perk up.

I recently saw one, but you had to put your head in both sequentially. If you repeated it often enough it also gave you hot water....

[Gary A]

Water cooled air conditioners are much more efficient, BUT we only run the air conditioner on hot nights and we need the hot water during the day, so one of the main benefits cannot be efficiently used.

[monty]

Basically only useful for hotels/resorts.

Tourists usually have the aircon running at all times they're in the room, plus in hotel rooms the run from the outside unit to the bathroom is usually not very long.

For private use if you want to save electrics you're better of with a solar water heater.

[Naam]

there's no need to run the aircon when there is demand for hot water. these units or the additional unit for an existing aircon are installed together with a boiler. water in boiler is heated when the a/c is running (by means of an tiny recirculation pump) and if there is not enough heat from the a/c the resistance heater of the boiler kicks in.

the same system is used by solar heaters. a hot shower at night does not require sunshine at night.

aircons fitted with the hot water generating gadgets are only partly watercooled. the condenser must have the usual fan which has to run when the temperature of the recirculated hot water exceeds 40-45ºC as this would greatly reduce the a/c's efficiency (lack of liquifying the gaseous refrigerant pumped from the evaporator of the inside unit).

[Naam]

Plz let me know if u come across ceiling fans that can generate hot water or toasters that can flush the loo and I will perk up.

what about a treadmill with cockroaches attached to a generator to power your microwave?

[sbk]

Thank you to those posters who gave useful answers. Cheers, Dr Naam, for the explanation . Amazing to me how some people have so much time to give useless nonsensical answers.

We were planning on using it in bungalows so the distance is not an issue

So, just for clarification, would this be more cost efficient for a bungalow than a separate air con unit and in line hot water heater?

[Naam]

Thank you to those posters who gave useful answers. Cheers, Dr Naam, for the explanation . Amazing to me how some people have so much time to give useless nonsensical answers.

We were planning on using it in bungalows so the distance is not an issue

So, just for clarification, would this be more cost efficient for a bungalow than a separate air con unit and in line hot water heater?

i have no idea how much a unit including installation cost is in Thailand. without that information i am not able to render a clear answer. but from all indications it will save in the long run quite a bundle as the heat is "free" and the recirculation pump draws a miniscule amount of electric energy (15-20 watts).

edited for addendum:

-please don't forget to allocate space for the boiler-type waterheater when planning your new home. ambient temperatures in Thailand would of course allow an outside installation but that would look ugly like sin if not "covered up" properly.

-the drawings for the plumber have to be modified too as separate hot water pipes are required to the points of demand (washbasin, shower, kitchen sink, etc.). for inline water heaters only one pipe is necessary.

Edited July 29, 2007 by Dr. Naam

[Tyke]

Basically only useful for hotels/resorts.

Tourists usually have the aircon running at all times they're in the room, plus in hotel rooms the run from the outside unit to the bathroom is usually not very long.

For private use if you want to save electrics you're better of with a solar water heater.

Monty.

can u direct me to where I can get such a solar heater and the approximate cost?

[chownah]

Sbk,

Air con units are of varying designs and of varying efficiencies. It is possible that a company with a very inefficient design and consequently very low sales might design an add on unit to heat water to add some glamour and to create the illusion that it will save you money when in the end it might be less efficient....I'm not saying that this is what is happening or for that matter that it has ever happened....I'm only saying that it is a possibility and you (or someone else with more knowledge of these things) should look at the stats for the unit (air con and boiler and water circulating pump) and perhaps using estimates for consumption patterns do a calc for energy costs and do the same for an efficient stand alone aircon and hot water appliance.

Chownah

[Naam]

Air con units are of varying designs and of varying efficiencies. It is possible that a company with a very inefficient design and consequently very low sales might design an add on unit to heat water to add some glamour and to create the illusion that it will save you money when in the end it might be less efficient

i strongly beg to differ and claim that there is no recognisable difference in efficiency amongst the different brands of aircons. any difference is the subjective opinion of the owner. what i found out in many cases is that the owners/operators have no idea on what settings a unit should run depending on the individual demands.

the hot water units which can be added are around since many years and save money when the purchase price plus installation cost is "right". however, i am not aware that any aircon manufacturer produces units which include the hot water unit.

[elkangorito]

I once looked after a large block of apartments in Sydney (Balmain Cove), which used these refrigerated heat exchangers. They were a disaster. The units used in situ were a storage tank with a compressor plonked on top. They are made in Australia.

Problems now & potential problems.

a] The occupants were always complaining of a lack of hot water in the winter because the evap coils used to freeze up & the head pressure was too low to heat the water to any reasonable temperature. This was also using R22, which can sustain high head (condensor) pressures (& therefore produce hotter water). It appears that these things work better in a warm climates.

b] Balmain Cove Apartments are by a saltwater river (not the windy beach). These refrigerated heat exchangers were heavily corroded even though they were only 2 years old. Their construction design was quite poor, which allowed a high ingress of weather. The electrics suffered in particular.

c] Considering that R22 will be totally phased out & unavailable in 5 years, I feel that these units will become useless if used in a coldish climate. The gas that will replace R22 (I forget what its name is) has a considerably lower head pressure than R22 & therefore will not be able to produce water as hot as R22. This particular bit of info I got from my former boss, an air conditioning engineer of about 40 years.

Disregarding the above, I think these units are efficient & if used appropriately, can save considerable money on electricity costs. Care should be taken in selecting units of a good design. Preferable is the water storage type. If the units are to be installed outside, they should be minimum IP55 rated. They work better in warm climates. The elimination of R22 in 5 years will not affect the hot water temperature for those of us who live in Thailand.

[Naam]

these refrigerated heat exchangers...

are not the gadgets discussed here Kangorito. talk is about "add-ons" to aircon units which use a part of the heat provided at the condenser side free of charge.