General Solar Thermal Systems Information

General Solar Thermal Systems Information

Can I tie a solar thermal system into my existing system?

Yes, you sure can. There are very few systems in the US that will not accept a solar thermal upgrade, The only exception would be a steam system. Whether you have forced hot air, boiler with baseboard, sub-floor radiant, in-floor radiant or wall heaters you can very easily integrate a solar thermal system upgrade. We have systems that are designed for every possible option for you, the only question is- are you ready to start saving money and lower your carbon footprint?

Simulating Performance of Solar Thermal Systems

Solar thermal systems will behave differently depending on a few variables such as, the obvious, location but also angle of tilt (slope off horizon), orientation angle, temperature of inlet fluid and also daily ambient temperature. We can calculate the efficiency of collectors for various times throughout the day but given the dynamic nature of production vs. consumption, it is better to use simulation software to accomplish this. At Sunmaxx, we use Polysun Simulation Software . By using this software, we can very easily ascertain the estimated performance during the course of the year. If you are looking to get some general idea regarding BTU output for various sized solar thermal systems you can view the ratings section of SRCC at: http://bit.ly/hs5ADx

Reducing fuel bills and increasing solar thermal output

Q: What is the best way to reduce my fuel bills by incorporating a solar thermal system? A:Reduction +Reduction = Reduction This should come at no surprise to any of our readers but the single best way to save money on energy bills is by reducing your consumption. It is surprising to me still, to find that at least 90% of homeowners that purchase a solar thermal system to reduce their energy bills have made no other provisions for energy reduction. By simply changing shower heads and turning set point temperature by 5 degrees, a homeowner can reduce their DHW load by nearly 25%. When coupled with a solar thermal system they can approach, easily, a 75% reduction. If we look at a broader approach with a more holistic solution, the impact becomes greater, the payback goes down and the return on investment increases markedly. Take a look at heating systems for example as well. Many in the US require fairly high temperature setpoints in order to deliver high quality btus to the home. If we tie a solar thermal system into a home heating system that require such high temperature as 160-180 Deg F then we are sacrificing a considerable difference in collector efficiency. By reducing the temperature setpoint of the home heating system, installers can essentially get more BTU’s out of a Solar thermal system. The most important factor that determines collector efficiency (that you have any control over) is the incoming temp to the collectors, therefore the lower the incoming temperature is, the higher the output will be. In other words, you get more by requiring less. For example, a heating system in the North East Us that uses baseboard emitters requiring 170 deg F will see an average efficiency during the winter months of nearly 35% for Evacuated tube collectors, and much lower still with Flat Plates, IF the installer couples the system with setpoint reduction measures (i.e. outdoor ambient reset, lower temp heat emitters, radiant floor tubing replacing baseboard etc) then the total collectors efficiency can nearly double. This means MORE useable BTU’s!! REDUCTION in Load and REDUCTION in temperature means REDUCTION in payback!!

Keeping propylene glycol from freezing in my solar thermal system.

A: How do I prevent my glycol from freezing during those rare deep freeze nights? Q: Your glycol, although rated for very low temperatures may be un-pumpable at a temperature higher than you expect. This can cause you system to overheat when the sun comes out in the morning. To prevent this you can activate the antifreeze function in your SmartMaxx controller. This function will turn the pump on as soon as your sensor 1 reaches a pre determined temperature, say -5 degrees. This will run only for a few minutes and then turn off, thus keeping your glycol above the un-pumpable temperature.

How do I remove air from my system?

Question: How do I remove air from my system? Answer: Take a deep breath and let all your air out… of your Solar thermal system One of the biggest issues with a successful commissioning is air removal. Any time you spend with this detail will be time well spent. Air pockets become entrained within your HTF and like to find places to hide. Air pockets can form between your HTF and the inner wall of piping (especially with flexible piping) and can only be removed through persistence and time. Here are a few things you can do to help this process. First, be sure that your air purger is located on the high and hot side of your collector series. The hotter the fluid the less the ability for dissolved gasses to stay in solution and the higher the air vent, the more likely you will effectively remove trapped air that, due to its buoyancy, will rise to the top. Once you feel most of the air has been removed this way, you can shut that air eliminator off or remove it all together. If you install a Titan Power Plus collector, you will have a manual air bleeder permanently installed in your line set connections. If you install a ThermoPower collector, you will include an air vent that should be isolated and de-commissioned at this point. Now, down to the pump station. The UniMaxx pump stations have an integral air eliminator with a scoop that will allow entrained air to collect and be bled off manually by opening the valve up to a full turn until HTF comes out. This can be done each day for the first few days or periodically checked. Smaller systems will take much less time removing the air. Another way of enabling the removal of air is to run the pump at maximum speed during commissioning, this will help to break the friction that holds the bubbles to the inner wall thus forcing the bubble through and out. After words, you should adjust your pump speed accordingly. If air persists in your system, it will inevitably find its way to the suction side of your pump and cause cavitation and eventual pump failure. If your pump appears to be not pumping, it is likely that although it is receiving 115v, it cannot pump because of air pockets. Simply unplug your pump and manual override and give it a few minutes. Air will work its way out, pump can run and then you need to go back to the air purging steps. Please view our SunMaxx technical manual (linked) for further instruction in effective system commissioning.

Do I need to use glycol if I live in an area where I only have a few days of freezing per year?

Question:
Do I need to use glycol if I live in an area where I only have a few days of freezing per year?
Answer: If you live in an area that doesn't get below freezing often (less than 5 days per year) it is possible to get away with using water instead of glycol. In order to make sure that the water doesn't freeze you need to have your controller (ie. SmartMaxx DHW-Plus) run with freeze protection. The freeze protection setting monitors the collector temp and when it goes below a specified temp (40 F) the pump will kick on the circulate the fluid which will prevent the water from freezing.