Commercial Solutions
Frequently Asked Questions
1. Is solar thermal energy efficient?
Solar thermal energy can meet up to 60% of your energy requirements for water heating. This is due to daily meteorological variations and to seasonal variations in daylight; it is also difficult to store heat from the summer sunshine for use in the winter darkness. For that reason, your current water heater stays in place as a back up system, allowing you to meet all of your water heating needs if the sun does not cooperate.
2. Under which conditions are solar collectors active?
Solar collectors are heated by solar radiation no matter what the outside temperature. A solar thermal system is nearly as effective in the winter as it is in the summer, whether it is 30°C or +30°C. Even in the presence of clouds, as long as some light reaches the solar panels, the solar thermal system will work to some extent. Solar thermal systems work in Canada and elsewhere in the world and are an accessible solution for water heating.
3. Can a solar thermal energy system help me save money?
The use of a solar thermal energy system reduces the consumption of electricity, fossil fuel or gas. On average, the savings generated with the use of a solar thermal system will cover the initial investment cost within a period of 5 to 20 years depending on your location, the local cost of energy, and the level of grants available from the government. A solar thermal system has an estimated lifespan of about 25 years.
4. Can I install my solar system anywhere, any time?
Like any other construction or renovation project, it is important to check with your municipality to inquire about the need for a permit and/or if there are installation restrictions for solar thermal systems.
5. Does a solar thermal system require a lot of maintenance?
When a solar thermal system is professionally installed, little maintenance is required. The maintenance regime is as simple as a yearly visual inspection of the system in order to ensure the solar panels are in good condition, and replacing the heat transfer fluid1 about every 5 years. Moreover, solar panels are self-cleaning and snow will melt off during winter. Finally, HLT Energies can be contacted to change the heat transfer fluid or to do any maintenance work to ensure the health of your solar thermal system.
1 Propylene glycol is the heat transfer fluid used in solar thermal systems to capture the sun’s energy and transfer it, through a heat exchanger, to your domestic hot water supply.
6. What is a heat transfer fluid?
A heat transfer fluid is a gas or liquid used to move heat between one or more sources of different temperatures.
HLT Energies uses a mixture of food-grade, non-toxic propylene glycol and distilled water as a heat transfer fluid and antifreeze. The ratio of propylene glycol to water is determined according to the expected temperatures in the solar collectors. The most common mixtures are 50/50 or 60/40 glycol-to-water ratio.
7. Do financial incentives exist to support going solar?
The Canadian government has put in place incentive programs to encourage you in your choices to protect the environment. The ecoENERGY program provides support for the residential, industrial and commercial sectors. Visit the following links for more information about the various programs developed for each of the sectors.
- Grants for Residential Property Owners
- ecoENERGY Retrofit Incentive for Industry
- ecoENERGY Retrofit Incentive for Buildings
Provincial and municipal incentives are also available to Canadian residents and businesses. HLT Energies can provide information about certain specific jurisdictions.
8. Is it possible for solar collectors to freeze or overheat?
The risk of freezing your solar collectors is eliminated by the use of propylene glycol, which has antifreeze properties.
When a solar thermal system is professionally designed and installed according to the estimated energy needs of the client, and when hot water is used on a regular basis, the risk of overheating the system is reduced or eliminated. Overheating is of concern when the system is left unused during prolonged sunny periods. If the system were to begin to overheat, the fluid expands harmlessly into an expansion tank. In large commercial systems, if the water in the storage tanks exceeds a safe temperature, hot water is released from the system and replaced with cold water. As a final safety measure, each system is equipped with a pressure release valve that will open and let out heat transfer fluid from an overheating system; this prevents system damage. When this extremely rare situation occurs, the heat transfer fluid must be changed, because high heat changes its properties and prevents it from doing its job properly.
9. Are there different types of solar thermal collectors?
Three types of solar thermal collectors exist: flat plates, vacuum tubes and concentrating collectors. The choice of collectors depends entirely on the client's goals for their system.
HLT Energies favours the use of flat plate solar collectors. Flat plate collectors are built within an insulated frame that is closed off with a glass or plastic pane on the sunny side. The interior is made of black metal sheets which absorb the sun’s heat. The heat, or thermal energy, is then transferred to water, air or some other heat transfer fluid which flows through tubing within the collector. The temperature differential between the ambient temperature and heat transfer fluid temperature can easily attain +70°. This differential is ideal to produce hot water for domestic use or space heating.
Vacuum tube collectors collect the sun's heat using glass tubes that have been sealed and emptied of any air which could transmit heat back to the surrounding air. They permit a greater efficiency of heat transfer, but only for the more limited surface area which they cover (because there must be spaces between each tube). They are also more fragile and more expensive than flat panel collectors, but are useful in particular circumstances.
Concentrating collectors are often configured as long troughs which reflect and concentrate the sun's rays on a black pipe containing a heat transfer fluid (often a liquified salt). Concentrating collectors are highly efficient and permit the production of heat which varies from 100°C to 400°C. This has advantages in situations where the objective of the system is to produce steam, for example for electricity generation. It requires that the panels be turned to follow the sun during the day, and it creates systems which cannot easily be put on a rooftop.