Glacier Chiller Install

[Baltimore_1]

Hi, @GrandLSU

We are planning on building a pool in Baton Rouge and I am very curious as to whether the Glacier chiller unit worked for you. Swamp coolers are not designed to work well in high humidity climates but, oddly, it appears that many customers (principally in Houston) claim that they are seeing 5-10 degrees of cooling even if the humidity is high (RH>70%).

Note - we are considering purchasing the Glacier GPC-210 (30K gallon cooler) for a 20K gallon pool. Our other option is to use a heat pump to chill the water which we know will work but may be much more costly to run. We are even considering purchasing both units and having them work together (in this scenario we would use the heat pump during very humid conditions). According to basic math, it will cost us about $10 to use a 20 SEER heat pump to decrease the water temperature of the 20K gallon pool by 10 degrees F (20,000 GAL x 8.33 LB/GAL x 1 BTU/LB x 10 x 1 KWH/20,000 BTU x $.12/KWH). Over the course of a long, hot summer that could get super expensive.

Your input would be greatly appreciated. TY!

 

[ajw22]

Welcome to TFP.

I think the trick is to run your filter pump and swamp cooler at night to cool down the pool for the next day.

Let's see if some folks int he South will confirm that is the way they run their Glacier Coolers.

 

[Baltimore_1]

Hi,

We intend to construct a 20K gallon pool in Baton Rouge, Louisiana. My understanding is that evaporative cooling systems like Glacier pool chillers do not work well in very humid conditions (i.e. relative humidity > 70%). Oddly, however, several members (principally in Houston) have posted threads over the past years indicating that their Glacier pool chiller seems to work well despite the high humidity (see - Does your pool feels like a spa? Get a Glacier Pool Chiller).

We may purchase the Glacier 30K gallon pool chiller (GPC-210), but we would first prefer to get some constructive feedback from members who have actually installed a Glacier pool chiller in a humid climate. Specifically, we are targeting substantive cooling performance in the range of 5-10 degrees F (and not 1-3 degrees F). According to basic math, it will cost us about $10 to decrease the temperature of our 20K gallon pool by 10 degrees F using a 20 SEER heat pump (see formula below) without accounting for additional heat gains during the cooling process (therefore real cooling cost will most likely exceed $10). This could prove extremely cost prohibitive over a long, hot summer.

Cooling Cost of Heat Pump = 20,000 GAL x 8.33 LB/GAL x 1 BTU/ Degree F x 10 Degrees F x 1 KWH/20,000 BTU x $.12/KWH = $10

Because evaporative cooling does not work well in humid conditions (because of the high dew point), the only logical explanation for the system performing well in humid conditions would be due to Glacier pool chiller operators running the unit at night when the air temperature is cooler than the temperature of the water in the pool. My theory would be that the unit is able to more efficiently dissipate heat by mixing the hot surface water from the pool (that has had all day to absorb energy) with the cooler night-time air rather than allowing the hot water to remain stagnant in the pool where it remains hotter because it is effectively thermally insulated by the surrounding hot water.

Please share your thoughts and experiences regarding the performance of Glacier pool chillers in humid conditions. Real world examples would be ideal. TY!

 

[KevMo]

I have a Glacier GPC-210 in the greater Houston area. It works well for me. I started off running it from 8pm to 9am in late July. On days when I did not run it overnight the water temp would rise to 94-96F during the late afternoon. With the chiller running overnight the morning temp would be down 82-84F. I credit the chiller with dropping it around 8 degrees over what it would otherwise drop to. I cut it back to 9-1/2 hours in late August. I have not needed it in the last couple of weeks.

I ran it for a few minutes during a couple of very hot & humid afternoons. The water coming out of my dedicated pipe was noticeably cooler than the rest of the pool so I could probably drop it more if I ran it during the day well.

I installed it myself and it took a little bit of tuning to get it working right.

 

[Baltimore_1]

KevMo,

Thanks for the invaluable input!

My response:

1. I assume that you got good results on humid days (i.e. RH >70%) and better results on less humid days. Please confirm this if possible. Note - I lived in Houston for 20 years and it seems that almost every summer day was oppressively humid.

2. What size is your pool (in gallons)? Did anybody suggest that you oversize the chiller? I am building a 20K gallon pool and we are considering the GPC 210 (30K gallon pool) and possibly even the GPC-215 (45K gallon pool). Besides cost, the primary negative with oversizing the chiller is the colossal size of the GPC-215 chiller (60" H x 46" D for GPC-215 versus 54" H x 42" D for GPC-210).

3. Did you ever consider a heat pump chiller? It appears that the cost of cooling the water is quite costly over time. My calculation shows that it would cost between $10-$20 to cool water / day (for a 20K gallon pool) by 10 degrees which equates to an additional $300-$600 per month in electricity costs.

4. I believe the GPC-210 unit does NOT have an overflow alarm which means that if the sump pump fails, you would drain your pool into your backyard. Is this a valid concern for you?

5. Are you generally satisfied with the GPC-210's performance? Would you purchase it again if you were building a new pool?

TY!!!

 

[KevMo]

KevMo,

Thanks for the invaluable input!

My response:

1. I assume that you got good results on humid days (i.e. RH >70%) and better results on less humid days. Please confirm this if possible. Note - I lived in Houston for 20 years and it seems that almost every summer day was oppressively humid.

The oppressive heat continues incessantly. The morning humidity is typically >70% and drops down to the low 50s. I haven't tracked the overnight water temperature change relative to the temperature and humidity. In addition to evaporation some of the cooling effect takes place by increasing the surface area of the water exposed to the cooler night air as the fan pulls air across the small drops.

2. What size is your pool (in gallons)? Did anybody suggest that you oversize the chiller? I am building a 20K gallon pool and we are considering the GPC 210 (30K gallon pool) and possibly even the GPC-215 (45K gallon pool). Besides cost, the primary negative with oversizing the chiller is the colossal size of the GPC-215 chiller (60" H x 46" D for GPC-215 versus 54" H x 42" D for GPC-210).

My pool is 27,500 gallons. I have the GPC 210. Noone at Glacier suggested oversizing it. Even the 210 takes up a lot of room on the pad. When I first installed it I wasn't getting the results I wanted. I spent a couple of weeks experimenting with the speed of the wands and the volume of flow that could be pushed to the pool. The key for me was to make sure the wands were dispersing water across the full area of the baffles and the sump could empty as quick as possible. I ended up removing the nozzle on the ededicated line to the pool to increase the flow. For reference, mines cycles about every 5-1/2 minutes. The sump pump runs about 30 seconds and it takes around 5 minutes to fill the basin enough to trigger the pump. I could probably shorten the fill time by a minute or so without the wands throwing water out the sides. I may try that soon.

3. Did you ever consider a heat pump chiller? It appears that the cost of cooling the water is quite costly over time. My calculation shows that it would cost between $10-$20 to cool water / day (for a 20K gallon pool) by 10 degrees which equates to an additional $300-$600 per month in electricity costs.

I looked st the cost to power and wrote it off. I already pay for 11 tons of AC and I didn't want any more. The chiller is far cheaper to run.

4. I believe the GPC-210 unit does NOT have an overflow alarm which means that if the sump pump fails, you would drain your pool into your backyard. Is this a valid concern for you?

That is correct. Glacier does not provide any solution for overflow (e.g. sump pump failure). I do worry about it a bit. I don't run it if I am out town. Based on the location of my equipment pad, flooding the yard would not worry me. It is more about losing water from the pool. I autofill from my private well, but I don't want the water level to get too low from chiller dumping water.

5. Are you generally satisfied with the GPC-210's performance? Would you purchase it again if you were building a new pool?

I am generally satisfied. I would purchase it again. It has made a difference in how much we enjoy the pool on the blistering hot days. A few aspects of it could be better engineered (e.g. overflow protection), but it works well enough.

TY!!!

As a side note, my acid consumption does rise when using the chiller on a regular basis. I already have a high acid demand so the relative increase is bearable. During peak times, I go through about a gallon a week. I but it 4 gallons at a time from HD.

 

[Baltimore_1]

Kevmo - thank you for your well written and detailed response.

Do you have an optimized approach as to when to run this unit?

Per your email above, the surface area of the pool water increases when it is chilled using your unit (water droplets cascading off wands have greater total surface area than the top layer of pool). I believe this is a textbook example of conduction (the transfer of energy when molecules collide with each other) and in theory would validate cooling performance during high humidity conditions (as long as ambient air temperature at night < pool water temperature). In addition to conduction, evaporative cooling would be the other main cooling process acting on the hot water in the pool.

Assuming this is correct, I believe it would be prudent to run the unit according to the schedule below:

Run chiller at night if ambient air temperature is less than the water temperature or if relative humidity is low (RH<80%+).
Run chiller during the day if ambient air temperature is less than the water temperature (very unlikely) or if relative humidity is low (RH<80%+).

My assumption is that when running the unit during the day, the cooling effect related to evaporative cooling will outweigh the conductive heat gain if the ambient air temperature > water temperature (very typical).

Thoughts?

 

[KevMo]

Kevmo - thank you for your well written and detailed response.

Do you have an optimized approach as to when to run this unit?

Per your email above, the surface area of the pool water increases when it is chilled using your unit (water droplets cascading off wands have greater total surface area than the top layer of pool). I believe this is a textbook example of conduction (the transfer of energy when molecules collide with each other) and in theory would validate cooling performance during high humidity conditions (as long as ambient air temperature at night < pool water temperature). In addition to conduction, evaporative cooling would be the other main cooling process acting on the hot water in the pool.

Assuming this is correct, I believe it would be prudent to run the unit according to the schedule below:

Run chiller at night if ambient air temperature is less than the water temperature or if relative humidity is low (RH<80%+).
Run chiller during the day if ambient air temperature is less than the water temperature (very unlikely) or if relative humidity is low (RH<80%+).

My assumption is that when running the unit during the day, the cooling effect related to evaporative cooling will outweigh the conductive heat gain if the ambient air temperature > water temperature (very typical).

Thoughts?

I agree with you. I have only run mine during the day for about 15 minutes on couple of occasions to see if it wasncoolr than the pool water when air temp > pool temp. I did note the humidity. In Houston, a summer day may start around 80% RH and dip to around 50% by late afternoon. For an example, it is currently 5:15pm and it is 93F and 50% RH for a heat index of 98F.

 

[TinFoilHat]

I would only run it at night as I do my aerator and then only in the afternoons before kids come over to swim. In essence it's just a huge version of my 3/4" aerator which during our hottest 110+ days is not enough at all.