## What's up 2007 team?

Hi, this is Aaron Antrim, one of the project team members from 2006. Feel free to bounce stuff my way during your work this summer. What's the present condition/status of the system? --Aaron 00:23, 15 July 2007 (PDT)

## C'est la vie

Hola Aaron,

Oh la la, the present condition/status of the system? Well considering we haven't touched it yet, probably about the same as when you left it. When we first sat down to talk with Nacho about it, he was telling us that it works great and they use it when they want the pool a little warmer in the summertime. Then when we were down there checking it out, the maintainance guy told us that they had turned it on once, but the pump "got tired" and hot, so they turned it off.

Currently we are waiting for Nacho to come back from Saltillo with some special PVC parts. According to Oswaldo, a plumber friend of the boys, we need to hook the system up so that the main pool pump pushes the water to the roof. While that is happening we will check the amps to see if the work load stresses out the pump too much. If not, cool, we don't have to think about buying a new pump. From that we can supposedly get some figures to plug into an equation to see how big the system would have to be to actually get the pool up to 80ºF. My question is this: what is that equation? How in the world do we actually figure out how big the system needs to be? How do we make the connection between the prototype and the real deal? Any ideas you can supply us with would be more than appreciated. All the research I've found thus far on the internet is extremely vague and ends by saying that working with a professional es el mejor. Thanks for nothing! is always the feeling I come away with. I'm sure your'e quite intimate with that feeling after working on this project last year?

Muchas gracias, Carolina --waterfaery72

### How to calculate the necessary size of the system

Well we started trying to answer that same question (what system size is necessary to heat the pool to the desired temperature) last year. Here was the way we thought to figure it, if I remember correctly:
(1) What is the rate of the pump and volume of water contained in the solar collector? How much water is cycled through per minute (volume of water processed) and how long does it stay in the collector (how many degrees hotter will the water be when it's returned to the pool).
(2) How much of that heat will be lost, and how quickly, from the pool. There will be some cooling that happens in the pipes that come down from the roof (could be reduced with insulation). But you may be able to find equations to help calculate how much heat will be lost based on the surface area of the pool, or another approach might be to measure how much temperature loss occurs in the pool overnight. I have no idea how the rate of temp loss will be affected by a great temp. difference between pool and air in winter. Oh, as a side note, a pool cover is super-important for having any hope of making this system viable in the winter.
In short, what we were trying to do was calculate (Temp gain from the system over the course of a day) minus (Temp loss from heat transfer in the pool over the course of the day/night). Good luck! --Aaron 13:17, 23 July 2007 (PDT)

## One 2007 Team Member Reflects a.k.a Jonathan

```August 11th, 2007
```

As individuals within a team we all experience and value certain aspects of our experiences differently. For that, I would like to add some personal notes on the development of the Perote project.

• Miscommunication, lack of communication, or misunderstanding has led to an inappropriate use of time, money, materials.
• There is a lot to be learned from this.

Tybie writes in her winter notes that in asking why her teams design had not been implemented that the technicians told her that the design need to be changed and they were waiting for the next team to approve the new design. Tybie did not personally take credit for approving the new design and left out whether she had and how she consulted her team about the change. But she does mention that construction of the new design was completed during her winter visit. This is unfortunate for our team had to wrestle with the politics and economics of reconstructing the system. This was a great learning experience on our behalf but it was also very time consuming, and a tad exhausting for those involved.

• Nobody likes to be told that a mistake was made and we'll have to go back and do it again - especially when their time, money and property is involved.
• In my opinion this error, while not fatal by any means, has negatively effected Ignacio's opinion of the project and has swayed his confidence to move it forward.
• Mistakes were made, waste is involved, and we have responsibility to acknowledge and correct that.

It is unfortunate that our team was not able to pull together the commitment and resources necessary to reconstruct this aspect of the system so that "Nacho" could feel good about where things are at, and next years team could jump right in to focusing on testing flow and temperature, collector expansion and/or moving in the direction of sourcing a more appropriate collector.

Another aspect of the unattended construction and faulty design in connecting the collector to the pump system is for some reason Ignacio's workers felt compelled to tell him that the system is was working fine, they run it and it makes a difference in the temperature of the pool, but not much. That would have been very nice were it true, but it is not and we had to tell Nacho so on as well as that in our opinion the work was a mistake.

• After bringing Ignacio together with our plumber and his technicians he is now well aware of where the system is at and what needs to be done to get water running through the collector in our opinion.

I have talked with him about it a few times since and tried to cultivate confidence in that regardless of where he goes from here he was going to have to address the pump issue to get water up to whatever collector he would ultimately invest in.

• We assured him that we would test closely the amperage and temperature of his filter pump in insure that it can handle the added work load - I am fairly confident it can since most all systems we've researched worked in this pattern.
• Ignacio is very careful with his money and it may require team contribution at the very least to reassert confidence in him of our commitment to the project.

To work that is required to realign the pump system to work with the filtration system is minimal and should be inexpensive. Their is not doubt one could do it themselves but I strongly recommend that you work with Ignacio's technicians or volunteer to source a plumber from town to keep things suave.

• Our plumber, Oswaldo Alvarado, is amiable, smart, familiar with the project and where it's at, and speaks a good english - which was integral to airing things out and bringing it together in my opinion.

Oswaldo, among other things, runs a little Bomba shop on Ramos Arizbe west of La Reforma and lives next door. He can be tracked down there - he's happy to help.

• Polypropylene and Evacuated tube collectors are manufactured domestically by Heliocol Mexico.

More research needs to be done, but based on what we have, one will find that in warmer climates polypropylene dominate the solar pool heating market because they are cost-effective and work we in warm conditions. Mexico Solar is an installer based out of San Miguel de Allende that appears to do a lot of work with polypropylene collectors. Relevantly, San Miguel de Allende has a very similar climate to Parras de la Fuente in terms of average lows during the colder months: click on the pueblos to see average temperatures.

• Evacuated tube collectors may be the most effective way to keep the pool a comfortable temperature in the colder months and in indirect light.

If ultimately it is the goal of Ignacio to extend his swimming season to year-round or near that, evacuated tube collectors (ETC) may be the most appropriate technology to meet that goal. While per meter squared it is true ETCs are relatively expensive to alternatives the amount required to heat a large body of water is significantly less. Based on the calculations of a UK ETC company it would take roughly 8 ETC's to get it done. That figure may actually be significantly lower considering average temperatures in the UK relative to here.

Be aware that I've heard through the grape vine that their is a significant leak in the filtration system that Ignacio has been able to isolate between the pump station and the pool. This is another set back for us as well as it is said that the leak is bad and for that reason the system is being run very infrequently which would explain numerous dirty pool sightings during even events such as weddings. I have been told the problem with fixing the leak is that one would have to dig up the new terrace along the lines, completely, to isolate and repair the leak.

• The leak would have to be addressed along with our pump/collector correction before any serious attempts at warming the pool vis-a-vis solar thermal collector can be had.
• A pool cover is the cheapest, easiest to use and maintain, and most effective technology that could be utilized to prevent heat loss.
• Solar thermal collectors can work in Parras!

This is a great project that warrants engagement. Ignacio has given us a great opportunity to work in a commercial setting to construct a solar hot water system in the middle of a 500 years old hacienda. Super padre!

See also: For more info on San Miguel de Allende

```~Jonathan Linton
```
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