 | The use of solar energy
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Although not a sun destination, the province of Quebec is nonetheless an ideal location for capturing solar energy. As a matter of fact, the City of Montreal has more solar energy potential than either Paris or Berlin, which have been using solar technology longer and to a greater extent than Montreal. The following table, which is an excerpt of a table found on the Natural Resources Canada website, shows that many other Canadian cities rival major cities around the world when it comes to solar energy potential.
Table 1: PV1 municipal rankings in terms of yearly PV potential2
Canadian cities | Yearly PV potential (kWh/kW) | Cities worldwide | Yearly PV potential (kWh/kW) |
| Regina (Saskatchewan) | 1361 | Cairo, Egypt | 1635 |
| Calgary (Alberta) | 1292 | Capetown, South Africa | 1538 |
| Winnipeg (Manitoba) | 1277 | New Delhi, India | 1523 |
| Edmonton (Alberta) | 1245 | Los Angeles, U.S.A. | 1485 |
| Ottawa (Ontario) | 1198 | Mexico City, Mexico | 1425 |
| Montreal (Quebec) | 1185 | Sydney, Australia | 1343 |
| Toronto (Ontario) | 1161 | Rome, Italy | 1283 |
| Fredericton (New Brunswick) | 1145 | Rio de Janeiro, Brazil | 1253 |
| Quebec City (Quebec) | 1134 | Beijing, China | 1148 |
| Charlottetown (Prince Edward Island) | 1095 | Washington, D.C., U.S.A. | 1133 |
| Yellowknife (Northwest Territories) | 1094 | Paris, France | 938 |
| Victoria (British Columbia) | 1091 | Tokyo, Japan | 885 |
| Halifax (Nova Scotia) | 1074 | Berlin, Germany | 848 |
1PV = Photovoltaic (Photovoltaic solar energy is electricity produced through the conversion of sunlight.)
2South-facing PV panels with latitude tilt
Solar energy is used actively to produce electricity and passively to produce heat. This article will deal with the passive energy used in buildings.
Heat production
When solar radiation comes into contact with a surface area, heat transfer occurs. For example, when a black car is exposed to the sun all day, heat builds up on the metal surface, which in turn becomes a source of heat to the immediate environment. Similarly, the exterior walls of a building envelope are exposed to the sun’s direct energy throughout the day. The sun heats and penetrates the walls, but as the sun sets, the walls release the radiant heat back into the environment.
How can we recover this energy?
The energy used in buildings
In Canada, a large proportion of the energy consumed by buildings is for heating requirements. This energy comes from a variety of sources including electricity, fuel oil, natural gas and propane.
Choosing a solution to save energy makes good financial sense since heating the building more effectively will result in recurrent cost savings. But first, it is important to consider all the relevant elements of the building envelope. Exterior wall construction, building orientation and heating are just some of the elements that affect total building efficiency.
Buildings require a constant supply of fresh air. This air is intended to replace the indoor air that would otherwise become stale and undermine the health and comfort of the building’s occupants. Through infiltration or mechanical systems, the supply of fresh air is a necessity and must be heated in winter to prevent it from cooling the interior of the building.
As we noted earlier, a large amount of energy is available from the sun. Since sunlight is free, why not use it?
Ventilated thermal panel (VTP) (Canam product)
There are many types of solar collectors. Canam Canada’s solar collector is a ventilated thermal panel (VTP) which is integrated into its shop-fabricated Murox® buildings. The primary purpose of the VTP is to preheat new air by means of solar energy.
For example, during the coldest winter months, the temperature of the incoming fresh air can be as low as -30°C. It must therefore be heated to a comfortable temperature for human occupancy. The VTP makes it possible to preheat this new air by as much as 19°C, depending on the intensity of the sun’s rays. The amount of energy collected from the sun is used to raise the temperature of the air supplied through the building’s mechanical systems. As a result, less electricity, gas or fuel oil is needed to heat the building. This results in significant savings in energy consumption which in turn reduces energy costs.
The VTP is a backpass-type solar collector whereby outside air enters at the base of the wall and is gradually warmed through contact with the thermal panel as it rises to the top (see Figure 1). Air travels up the wall in four stages as follows:
1 - The air is drawn in at the base of the wall.
2 - It is warmed by the metal cladding that lines the interior wall.
3 - The preheated air is directed towards a duct connected to a make-up air unit.
4 - The mixed air in the system is heated to the desired temperature before it is distributed throughout the building.
Figure 1: Ventilated thermal panel (VTP)
Conclusion
VTP technology can easily be installed on most industrial and commercial Murox® buildings. For optimum performance, the wall must be as dark as possible and ideally have a southern exposure.
It is important to note that the VTP is maintenance-free.
Installing the Murox® VTP is a cost-effective way of helping to reduce energy bills, while contributing to green building initiatives. What is good for sustainable development is good for the environment.
Information
For more information, please contact our experts:
- Telephone: 1-877-499-6049
- Online: VTP
Our projects
Consult the list of projects completed by Canam Canada.
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