Water Cooled Compressor?

[Joybob]

This is my first post here so I'm sorry if I don't understand the Jargon correctly. I've had an idea in my mind for a while now and I was wondering if it was feasible.

My current electric bill is pretty high and most of that is due to air conditioning. In my area it rains every other day so it occurs to me. Why can't I route all the water that collects on my roof, send it down a drain and solder half a pipe to the coil on the compressor of an air conditioning unit in a counter-current configuration. Since rain seems to be pretty cold and it has a much higher heat capacity than air it seems like that would make the air conditioner more efficient.

I was wondering if this:
1. Is feasible.
2. Will it actually save me cash of my electric bill?
3. What A/C unit would be best suited for this kind of modification.
4. What method would be good for coupling the pipe carrying rain water with the compressor coil?
5. Has this been done before?

[taz24]

I was wondering if this:
1. Is feasible.
2. Will it actually save me cash of my electric bill?
3. What A/C unit would be best suited for this kind of modification.
4. What method would be good for coupling the pipe carrying rain water with the compressor coil?
5. Has this been done before?

In what way do you think this would save you money?
Do you intend to use the water for showers or baths or is it to be wasted, after being used purly to cool the condenser (the name for the coil with the comp)?

If it is to be for cooling and then the water is to be wasted then the only saving would be in not running the cond fan.
A saveing but a small one.

You need to elaborate a little bit more.

Cheers taz.

[progzmaster]

1. Is feasible.
3. What A/C unit would be best suited for this kind of modification.
4. What method would be good for coupling the pipe carrying rain water with the compressor coil?

I think this is simply feasible. Drill a lot of radial holes to a tube. Feed the water at one end, the other end need to be closed, and place the tube horizontally above the coil with the holes facing down. Drill few bigger holes to the bottom of the case to allow the water to flow out.

2. Will it actually save me cash of my electric bill?

The efficiency of the unit will increase, the cold side will colder, so I think you can save some cash...

[Joybob]

In what way do you think this would save you money?
Do you intend to use the water for showers or baths or is it to be wasted, after being used purly to cool the condenser (the name for the coil with the comp)?

If it is to be for cooling and then the water is to be wasted then the only saving would be in not running the cond fan.
A saveing but a small one.

You need to elaborate a little bit more.

Cheers taz.

Well the water from my roof just goes off into the sewer so it's going to be wasted anyways.

[Tesla]

Hi joybob
5=yes this was a common method 20+ years ago, has been made illegal due to the waste of good clean drinking water for systems that discharge water into drain. In commercial buildings use a condenser water loop to circulate water to cool water cooled ac units, this now heated water is then cooled in a cooling tower by evaperation and recirculated.
4=Use a water catchment tank with a sock drainpipe strainer. If you had a big (4000l) tank you could use it for washing in the house. you may need a pump depending on the head pressure of water which would slightly offset savings in power.
3=Temperzone manufactures watercooled ducted ac units in NZ and Ausi. There will be other manufactures near you. Microbiol contamination - legionaires disease, maintenance costs become an issue.
2=yes - If you were installing new or replacing old system it would take a few years for payback but over the life of the plant it is feasible. To change a plant is not usually cost effective unless you have free labour and cheep materials. Either way it will save on your power bill but the cost of changing to water will be the biggest factor. calculateing the costs roughly - modification materials and labour against your savings, work out how much energy kwh the ac uses over a year and convert it to dollars/year. Then contact manufacturer for colling capacity/power consumption, do the same for existing units. take the difference as a percentage and apply percentage to your calculated cost/year. This will be your savings on power. Multiply this saving by the amount of years for lifespan of units say 10 - 15 years if your lucky. Take the cost of the project and minus the savings. Considering power costs more each year you could calculate increases durring the past 5 years and apply as a percentage/year - this will show more savings accuratly. Almost forgot maintenance for this system will increase
1=No unless it is going to be replaced or it is going to be cheep and simple. The biggest bang for your buck is likely to be minumising your current system costs with timers or motion sensors in cooled zones to reduce running times and having occupied and non occupied temperature setpoints. Look to see if you can save with shading sunny areas, building insulation, roof, air leaks, fresh air modulation, clean filters, open the windows on cool nights if you got insect screens that is.
Tesla

[Joybob]

I think this is simply feasible. Drill a lot of radial holes to a tube. Feed the water at one end, the other end need to be closed, and place the tube horizontally above the coil with the holes facing down. Drill few bigger holes to the bottom of the case to allow the water to flow out.



The efficiency of the unit will increase, the cold side will colder, so I think you can save some cash...

Follow up question. Would it be worth the effort?

[Joybob]

5. Tesla, would it be illegal to do this or not?

4. I was thinking of simply routing the rainwater from my roof to the condenser using gravity to drive the rainwater.

3. If the water is just going to go down the drain, why would bacterial infection become an issue?

2. I was thinking of a simple modification job. Just modify a small part of the condenser so that it can be cooled by rain water but leave the rest of the condenser intact so it can still function with the fan.

1. So if I stick to a simple modification job it might be worthwhile?

[Tesla]

Hi joybob
5 Because you use rain water No it is not illegal.
4 You could drissle the water accross the inlet of condenser and precool the air on a dry day like a swampbox, or drissle it across the coil when raining - does the fan suck or blow? it would be affected by the moisture. Extra maintenance but yes it would work and save a little on the power bill. If there are several units try it with one first then improve on the next. It should not cause any bio issues. Good luck.

[Joybob]

Hi joybob
5 Because you use rain water No it is not illegal.
4 You could drissle the water accross the inlet of condenser and precool the air on a dry day like a swampbox, or drissle it across the coil when raining - does the fan suck or blow? it would be affected by the moisture. Extra maintenance but yes it would work and save a little on the power bill. If there are several units try it with one first then improve on the next. It should not cause any bio issues. Good luck.

Well what I wanted was to somehow couple a pipe to a section of the condenser so water flow directly against it, but I can't seem to think of a simple way of doing that.

[Tesla]

Maybe use some garden/hydro sprinkler type fittings from local hardware and either spray or drissle water onto coil. Attach hoses with cableties. I've even seen a garden sprinkler system used for cooling condensers on a big building (rotten condenser).

[Ben-Hur-Cool]

Hey Bob,

another good question is
Is your condensor FAN a modulating (regulates speed) on or not? This could by temperature sensors on the coil or pressure regulated.
Because if it isn't, don't even bother cause your FAN is going to turn always when your compressor turns.

If it's a regulating one, experiment a little with the RAIN water, you will certainly save on your energy bill.

Greetz Ben