# energy saving Water cooled air conditioner in Yucatan



## RandomCoolzip (Jan 26, 2021)

Has anybody had experience using/installing water cooled air conditioners in the Yucatan, either commercial or residential? 
Any comments about other types/brands of air conditioners that energy saving?

Seems like good possibility to save energy in a climate so hot and humid. 
Thanks


----------



## RVGRINGO (May 16, 2007)

You seem to be describing Evaporative Cooling systems, which work well in hot and dry situations, such as desert areas. However, they add more humidity to your interior air, and are not at all efficient in humid climates. I suggest that you stick with conventional AC equipment if your climate is humid.


----------



## RandomCoolzip (Jan 26, 2021)

No, I am very familiar with evap cooling (ie. swamp coolers). Not appropriate for this climate. They make water cooled A/C units (mostly commercial) that have the heat exchange in the the cooler water so they are more eficient than air exchange. You may have seen cooling towers on roofs; that is where the heat exchange with the water occurs.


----------



## eastwind (Jun 18, 2016)

TL;DR: Yes.

I'm in Cancun. My apartment building has a chiller and pumps cold water throughout the building. The chiller runs on communal electricity. My 4 BR flat has 6 'blowers'. The blowers have a thing like an automobile radiator, only smaller, that the cold water goes through, and squirrel cage fans to blow room-temperature air across them to be cooled, which goes through ducts to vents in the rooms. The whole system, apart from the chiller, is up in the ceiling below the cement floor of the story above me.

The building is 20+ years old, and when I bought the apartment there were a lot of places where condensation had dripped down, and there was one leak in one blower that dripped water onto the kitchen floor, enough to fill a bucket in 2 days. The fans were loud and rattled. I renovated the entire apartment, including replacing all six blowers, all the chiller pipe in my apartment, and all the ceiling drywall. Now my new blowers are very quiet, all you hear is the air rush, not the fan itself, and there is no condensation anywhere except at two registers in the main room. And no leaks at all.

It is absolutely necessary to insulate every inch of the chilled water piping to avoid condensation. They used 1" think foam that came in tubes and shoved the tubes on a length of PVC pipe. They put black glue on the outside of the pvc pipe before shoving the insulation down it, so once on it is on for good. Then they hand cut and glued pieces of insulation at the fittings. There was one place where they didn't get a perfect fit, and I started to have condensation dripping there, easily fixed (they delayed putting the ceiling back up a couple weeks to test for these places).

The apartment originally used galvanized pipe for the chilled water, PVC is lighter, cheaper, and won't rust in 20 years.

The blowers come from China, and there was a significant order lead time.

The running costs of the system are significantly cheaper than split unit AC units, especially considering the chiller electricity is communally paid for (its cost is buried in my condo association maintenance fee, not on my electric bill).

The blowers come (optionally) with catch pans to collect any condensation that forms on the radiator, you need those. And you need a way for that water to drain into the drainage system. That pvc piping doesn't have to be insulated. 

When replacing the system, when possible, they fixed the grill vents to face down from the ceiling instead of out from a wall. When there is condensation, it thus drips down harmlessly on the tile floor.

If the sliding glass door to the balcony gets left open a crack a lot of humid air comes in, the blower runs overtime, and I get condensation on the grill in that room. If it is very windy outside I get humid air blown in through cracks around the windows that the renovation hasn't (yet) corrected, resulting in condensation.

If you get condensation up in the ceiling above they drywall, you will get black mold above the ceiling where you can't see it, until eventually you get discoloration of the ceiling due to the drywall getting wet. 

I think it's an ok system for an apartment building, if designed in and built in originally, or a large house. I don't think it's feasible to retro-fit it to a typical multi-story house without space between the ceiling and the floor above. It would work great in a one-story house with an attic. You need to be really 100% picky about preventing the condensation or you will have mold. You will have condensation because of the humid climate unless you have a really air-tight place, and in my experience those are not the norm here because it doesn't get cold.

It is apparently more economical for a large building than many smaller split units. I don't know where the trade off goes the other way - that is, I don't know how many blowers you'd need to have running to make it cheaper than the same number of split units. An AC shop would probably steer you to the cheaper solution if you get their advice. 

The system does have a lower bound on how cool it can get the rooms. In my place, they say we are all to set our thermostats to 23. In my bedroom, I set it down to 21.5, setting it below that will just make the blower run all the time without lowering the temperature any more than that.


----------



## MangoTango (Feb 8, 2020)

Gosh - and we have to open the windows and doors to warm up the house.


----------



## TundraGreen (Jul 15, 2010)

Where I am (at 1545 m elevation), I leave the doors to the patios open all year round. It is a little cooler than I like in December-January and a little warmer than I like in May, but livable all year with no source of heat or cooling.


----------



## izzenhood (Jun 8, 2013)

eastwind said:


> TL;DR: Yes.
> 
> I'm in Cancun. My apartment building has a chiller and pumps cold water throughout the building. The chiller runs on communal electricity. My 4 BR flat has 6 'blowers'. The blowers have a thing like an automobile radiator, only smaller, that the cold water goes through, and squirrel cage fans to blow room-temperature air across them to be cooled, which goes through ducts to vents in the rooms. The whole system, apart from the chiller, is up in the ceiling below the cement floor of the story above me.
> 
> ...



Eastwind

Thanks. Great explanation of the water cooling system; something I've never heard of.

I assume it's not used up north because the system would have to be drained in the winter.

I've heard that electricity is very expensive in Mexico, so somehow your communal electricity accounts for that. Then again one massive water refrigerating unit on the roof would be cheaper than individual AC units.


----------



## surabi (Jan 1, 2017)

izzenhood said:


> I've heard that electricity is very expensive in Mexico


Electricity is actually really cheap in Mexico as long as you don't go over a certain kwh usage. There are kwh tiers and the lower tiers result in low bills because it is govt. subsidized. Once you get into high usage, you don't get the subsidy.

My electric bills average about 200 pesos every two months. That's the equivalent of $5 US per month.

Thats for 1 person, running fans, lights, washing machine, water pump, fridge and kitchen appliances like toaster, blender, etc. And electronics like laptop and phone chargers. I also have industrial sewing machines.

What I don't have that racks up the electric bills is AC. Or a pool or a pressure pump.

If you want to live a first world lifestyle in a non-first world country, then yes, it can be expensive.If you live more like a Mexican, electric is dead cheap.


----------



## eastwind (Jun 18, 2016)

The price I pay varies depending on the time of year, even though my usage in kwh is relatively consistent. I'm about to get my biggest bill of the year, for the mid-December to mid-February period. It will be over twice, maybe even 2.5 times, the cheapest bills of the year (which are April-June and June-August). 

Mexicans say their electric bills are expensive, and given what they earn, they are. But I think the average US expat will see their total cost of utilities go down when they move here unless they add additional luxuries like swimming pools or hot tubs that they didn't have in the US.


----------



## MangoTango (Feb 8, 2020)

When you exceed a certain threshold (depending on what zone you live in) you enter DAC. I believe it is an average of your last 6 billing cycles (12 months). We (and most everyone else living at altitude) are in zone 1. We are allowed usage of 250 kwh/month. All you beach bunnies are allowed 2500 kwh/month. DAC is a bad thing and just as you average into it, you need to average your way out. There is a schedule posted on the cfe.gov website. And yes - there is a seasonal aspect as well. 

I believe usage is tied to the meter and not the owner of the account. It is important when you buy or rent that you have a look at some cfe bills. You may inherit a bad situation. Certainly when you rent because it is likely the account will remain in the owner's name.


----------



## surabi (Jan 1, 2017)

MangoTango said:


> All you beach bunnies are allowed 2500 kwh/month.


You mean without going into the DAC rate? If so, that is totally false. I live in a beach town. We have the same kwh/rate system you do. Anything over 250kwh in basic is in rate tier 2.


----------



## eastwind (Jun 18, 2016)

DAC isn't the same as being in tier 2, it's a penalty box status that raises your rates across the tiers.


----------



## surabi (Jan 1, 2017)

eastwind said:


> DAC isn't the same as being in tier 2, it's a penalty box status that raises your rates across the tiers.


Yes, I'm aware of that, sorry I wasn't clear. But basic and intermediate(tier 2) only allow about 400 kwh in total, then it gets into DAC rate. No one here on the coast gets 2500 kwh before going into DAC, which us why everyone I know with AC has installed solar, otherwise their bills are astronomical.


----------



## MangoTango (Feb 8, 2020)

The zones are determined based on the climate of a region.
There are 7 zones and the non-DAC usage ranges from 250 kwh/month to 2500 kwh/month.
I guess I was wrong to assume that all coastal area would have a different climate (in the view of CFE) than the central highlands.
And, while I believe the kwh rate varies based on season, I don't think the DAC thresholds vary.

https://app.cfe.mx/Aplicaciones/CCFE/Tarifas/TarifasCRECasa/Tarifas/TarifaDAC.aspx

Edit :
Found a map of the CFE zones.

https://3.bp.blogspot.com/-PBUDCz9v...CLcB/s1600/Regiones_tarifarias_CFE_Mexico.jpg


----------



## eastwind (Jun 18, 2016)

I'm in zone 1D, in spite of the map making it look like I'm in 1C. I think perhaps there's just a thin sliver of 1D that is too small to show up on the map.

Here is some data from my last two bills.

The 11 June to 11 August bill had a total of 623 kwh. 
Basico: 350 @0.747 pesos/kwh
Intermedio 1: 273 @0.872 

The 11 August - 12 October bill has 757 kwh:
Basico: 350 @0.751
Intermedio 1: 407 @0.876

The 12 Oct - 11 December bill has 643 kwh:
Basico: 150 @0.851
Intermedio: 250 @1.028
Excedente: 243 @3.011

First, note that the limit of "high consumption" for 1D is 1000 (from MangoTango's link), but I'm even always under the limit of 850 for 1C. In fact the history on the back of the bill shows no bill above 850 for the last two years. So there is no DAC penalty here at all, this is all regular schedule billing.

Second, notice how the limit for Basico goes down in the winter from 350 to 150. 

Third, notice how the price per kwh goes up in the winter, even for Basico. And Excedente is over 3 pesos/kwh!

Notice too that even though my usage went down from Oct to Dec, the limit on Intermedio 1 which was more than 407 kwh in october dropped to only 250. I believe that there is also an Intermedio 2 during the summer, but only just Intermedio in winter with Excedente starting at a much lower level in the winter - but that's not provable from these bills, it's based on memory from my other apartment where I went sometimes into Intermedio 2 during the summer.

The 243 kwh in Excedente during Oct-Dec cost only a couple pesos less than my entire bill for Aug-Oct, and more than the June-August bill. 

I expect my next bill to be higher even still, but still only about 1/4 per month of what I used to pay in the US every month of the year.

For me, the cost of electricity isn't a bad deal. I always feel I'm getting a great deal during the summer. Run the AC 24x7 and pay US$30 for two months? Yeah! Three cheers for the chiller! 

My new apartment is cheaper than the old one even though the new one has more AC blower units because I replaced all the blower units while the old fans in my old apartment (rented) were inefficient and expensive to run. The landlord replaced the fan motors right before I moved out and it made a noticeable difference in the last electric bill.


----------



## MangoTango (Feb 8, 2020)

You might have a different opinion if you lived in a decent sized house in Zona 01. 

But I will agree with you. Our utilities in Mexico are much cheaper than they were in Florida. If we didn't leave the pool pump on 24x7 then it must have been on 16x7 (I don't remember). We had two large a/c units, one for downstairs one for upstairs. (Fortunately we often had a nice ocean breeze and could open the windows). Our electric bill was several hundreds dollars. We also had huge water bills. In fact they charged double. We got billed for fresh water, and then we got billed even more for wastewater ! Again, several hundreds of dollars.

Here in our Mexican world there are often street protests in front of the CFE offices. Possibly the water company is CFE's largest customer and they often turn off the power because of non-payment. That causes more protests. 

On the positive side - we have had two electrical events recently. We have a large voltage regulator outside where our power comes off the street. One of the boards in the box (which had not been serviced in 16 years) burned out and all the lights in the house were flashing on and off like the evacuation lights in a US business building. Our hierro came over and rewired everything bypassing the regulator until we had it properly serviced. The second event was when the lights went from normal to very dull, again and again. We called CFE and they had a guy come out like in a couple hours. He pulled the meter and showed us how one of the wires in the grey box was a little singed. He thought it was not the proper gauge and replaced it for free. It has been fine since. In the US, FPL would have told us to hire an electrician...


----------



## eastwind (Jun 18, 2016)

I just got my bill for Dec-Feb. this is the first bill where I was running the new air conditioner blowers full time. The total usage is way down, to 420 kwh. The renovation certainly has made a difference. 

Energia (kwh): 420
Basico: 150 @0.855 p/kwh
Intermedio 250 @1.034 p/kwh
Excedente 20 @3.026

The total bill was $542 pesos vs 1,928 pesos a year ago. (when I used 814 kwh). that was the high bill for the last year.


----------



## MangoTango (Feb 8, 2020)

Make sure the bill is the result of an actual reading. There have been periods where we have gotten estimated bills.


----------



## citlali (Mar 4, 2013)

What is a hierro?


----------



## eastwind (Jun 18, 2016)

Good point, I checked and both the current and prior readings are "medida" not "estimada".


----------

