Frequently Answered Questions
Solar PV
- Will solar panels damage our roof?
- Are solar panels heavy?
- What happens when I have to replace or repair my roof?
- How much rooftop space do I need for a solar PV installation?
- Are all my rooftops suitable for solar PV installations?
- What happens after the 20-year lease expires?
- Does weather impact the solar PV’s?
- What about snow on solar PVs?
- How long will it take to complete the solar panel installation?
- How often is maintenance required?
- Are there any other benefits for the building owner?
- How long do solar PV panels last?
Geothermal Systems
- What is geothermal energy?
- What are the environmental benefits of geothermal systems?
- Where can the geothermal system be installed?
- Can the system be drilled in a septic field?
- How much space is required?
- How long will it take to install?
- How long will it last?
- Can geothermal systems be used for heating and cooling?
- What are the maintenance requirements?
- Will the boreholes lead to any contamination/damage/erosion to the ground or impact on surrounding structures?
- Are there additional benefits of using Geothermal for the building owner?
- In the case of a retrofit, can the existing ventilation system be used?
- Is it possible to combine geothermal with a traditional system?
- Is it necessary to have a back up supply?
- Can geothermal heat be used to generate electricity?
- Does Potentia install residential geothermal systems?
- Can geothermal systems be used to heat domestic hot water?
District Energy Plants
- What is district energy?
- What are the advantages of district energy?
- How reliable is district energy?
- What is combined heat and power?
Solar Thermal HVAC
- Can a solar water heating system be used in place of a traditional gas or electric heating system?
- Do solar thermal systems produce hot water in the winter?
- Do solar thermal systems still produce hot water on a cloudy/overcast day?
- Can I use a solar collector with my existing hot water system?
- What is the life of the solar collector systems?
- Do solar heating systems require any maintenance?
Solar PV
Will solar panels damage our roof?
Potentia uses ballasted racking systems to support the solar panels on the roof. Ballasted racking does not penetrate roof surfaces, leaving roof integrity fully intact.
Are solar panels heavy?
A solar panel installation, on average, adds approximately 2 to 5 lbs of load per square foot. Before any installation begins, Potentia conducts a structural survey of the roof to ensure that all solar PV installations can be completed safely and without damage.
What happens when I have to replace or repair my roof?
When roof replacement or repair is required, Potentia will work with the building owner to schedule all necessary work. Because Potentia’s racking systems do not penetrate the roof surface, moving panels is a relatively simple process.
How much rooftop space do I need for a solar PV installation?
A typical solar PV installation requires 160 sq ft per kW of solar PV capacity. Potentia targets installations between 100 to 250 kW, which would require 16,000 to 40,000 sq ft respectively of suitable rooftop space.
Are all my rooftops suitable for solar PV installations?
Not all rooftops are suitable for solar PV installations. Structural integrity, direct sunlight, square footage and a roof that is in good condition are all basic requirements for a solar PV installation.
What happens after the 20-year lease expires?
There are several options available to the building owner after the initial 20-year roof lease term expires. The building owner could purchase the system; renew the lease or; have Potentia remove the installation and restore the roof to its original state.
Does weather impact the solar PV’s?
It goes without saying that solar PV’s work most effectively when it is clear and sunny. Rain impacts the solar panels in a positive way as it serves to clear away dust and dirt that may have accumulated.
What about snow on solar PVs?
Fresh snowfall will generally melt off solar PV panels on its own if the sun is out. In some cases, such as after freezing rain, it must be cleared by hand. Potentia assumes responsibility for this service under our general maintenance obligations.
How long will it take to complete the solar panel installation?
Potentia crews require 2 to 4 weeks to complete a standard solar PV installation.
How often is maintenance required?
Potentia performs standard maintenance on solar panels four times annually, however, cleaning of the panel surface may be performed more frequently.
Are there any other benefits for the building owner?
National surveys consistently show the environment is a major concern for Canadians, resulting in demands on building owners to be environmentally responsible. A solar power installation on a building roof can help a building acquire LEED points and ultimately attract tenants.
How long do solar PV panels last?
Many solar PV manufacturers guarantee their panels for 20 to 25 years. Potentia only purchases high quality panels from best in class manufacturers who provide minimum 20-year performance guarantees.
Geothermal Systems
What is geothermal energy?
Geothermal literally means ‘earth-heat’ and refers to heat or coldness that can be captured from the earth and can be harnessed to use as energy.
What are the environmental benefits of geothermal systems?
By transferring renewable heat or coldness from the ground into a building, there is reduced need for of non-renewable energy to heat and cool the building. This leads to a reduction in the emission of pollutants and greenhouse gasses overall. Data from Natural Resources Canada and the US Environmental Protection Agency indicate that geothermal systems have the least environmental impact of any HVAC technology on the market.
Where can the geothermal system be installed?
The ground loop can be installed under parking lots, in basements or anywhere else on your property. Canadian standards require that the entire field of boreholes be installed at least four feet below the surface and covered for insulation purposes. This enables the space above the ground loop to be used for other purposes as soon as installation is complete. Cement, asphalt, and vegetation will not be affected by the buried ground loop.
Can the system be drilled in a septic field?
No. The fluid circulated in the ground loop system uses a water-alcohol mixture to prevent freezing and improve heat exchange. This may result in the freezing of the septic system in extreme conditions, reducing its capacity to decompose waste. For this reason The Canadian Standards Association guidelines for ground loop installation prohibit the use of geothermal systems in septic fields.
How much space is required?
The size of the field will depend on the thermal conductivity of the ground and heating/cooling requirements, which is determined with test drilling. Typical configuration for drill holes is 15 to 20 feet apart and 75 to 500 feet deep. For a general estimation, 100-200 feet of drilling depth yields about 12,000 BTU/hr (3.5kWh) of heating capacity.
How long will it take to install?
Site clearing and preparation will be on the order of weeks depending on the size of the field and/or removal of asphalt or concrete. Drilling time is dependant on rock conditions and can vary between 500 to 1500 feet per day (per drill). Expect drilling to take less than one month for a single building, to up to three months for large heating requirements or a basement installation. One to two weeks are required after drilling for circulation preparations and resurfacing.
How long will it last?
Geothermal ground loops use high-density polyethylene pipe which does not rust, corrode, or react with common soil and rock chemistry. Pipes can maintain their usability for 50 or more years, but as with all heating and cooling systems, system overhauls and mechanical equipment replacement will be required after 15 to 30 years.
Can geothermal systems be used for heating and cooling?
Yes. Geothermal systems are more effective when used for both heating and cooling. Absorbing heat in the winter and rejecting heat in the summer recharges the ground’s temperature on an annual cycle. Used only for heating the ground would cool over time. Energy savings for heating are usually in the 50-70% range, while cooling savings are usually 20-50%.
What are the maintenance requirements?
Potentia Energy performs standard maintenance a prescribed number of times per year, and will monitor the system performance to optimize heating/cooling capacity.
Will the boreholes lead to any contamination/damage/erosion to the ground or impact on surrounding structures?
No. Drill holes filled with pipe are grouted with cement to prevent surface water from contaminating ground water, damaging the holes or eroding the surface. The design ensures that the installation is not in contact with any surrounding structures of buried infrastructure. The drill holes themselves do not result in any geological, hydrological or temperature implications that might affect the surroundings.
Are there additional benefits of using Geothermal for the building owner?
Yes. National surveys consistently show the environment is a major concern for Canadians, resulting in demands on building owners to be environmentally responsible. Energy efficiency can help a building acquire LEED points (Leadership in Energy and Environmental Design) which could attract tenants and lower tax rates.
In the case of a retrofit, can the existing ventilation system be used?
Yes. Assuming the original ventilation system was properly designed for the building’s needs, a geothermal loop should be able to plug directly into the existing ventilation system.
Is it possible to combine geothermal with a traditional system?
Yes. Certain circumstances (climate, insulation, size constraints) can render geothermal systems uneconomical when designed to meet 100% of the climate control needs. A hybrid (or split) system can be employed to supplement the geothermal system’s capacity for buildings that experience temperature extremes during certain times of the year. Existing equipment can be easily used in these cases.
Is it necessary to have a back up supply?
Yes. In a non-hybrid system, a geothermal system is usually installed with a back-up electric heater in case of circulation pump or heat pump failure. It can also supplement the geothermal system in case of exceptional outdoor temperatures.
Can geothermal heat be used to generate electricity?
No. Geothermal heating systems use thermal energy stored near the earth’s surface. The temperature at the surface stratigraphic layer is around 10ºC, and results in an exchange of heat between the earth and geothermal heat exchanger boreholes. As a result geothermal heating is often called ‘geoexchange’. Geothermal power is generated when ground temperatures are in the hundreds, or thousands, of degrees Celcius, and are used to produce steam that drives electricity-generating turbines. Power generation requires drill holes thousands of feet deep or high volcanic/magmatic activity.
Does Potentia install residential geothermal systems?
No. Potentia only installs geothermal systems in commercial offices, light industrial buildings or institutional buildings such as hospitals and schools.
Can geothermal systems be used to heat domestic hot water?
Yes. In some geothermal designs it is possible to pre-heat domestic hot water using the geothermal system heat pumps which reduces substantially the heating requirement for a secondary fuel source – either electricity, natural gas or solar – to bring the water up to typical minimum domestic hot water requirements of 50 ° C (120 ° Fahrenheit).
District Energy Plants
What is district energy?
District energy systems produce steam, hot water or chilled water at a central plant and pipe that energy to buildings in the local vicinity or “district” for space heating, domestic hot water heating and air conditioning. As a result, individual buildings no longer need their own boilers or furnaces, chillers or air conditioners.
What are the advantages of district energy?
One district energy system can serve many customers from one location and can accomplish economies of scale that individual buildings seldom can. Some district energy systems can switch between a variety of energy resources, traditional or renewable fuels such as biomass, geothermal, and combined heat and power. Buildings on district energy systems also have lower capital costs for their energy equipment since they don't need conventional boilers and chillers. They save valuable initial investment funds that can be used elsewhere while freeing building space that can be used for more valuable purposes.
How reliable is district energy?
Building owners and managers can count on district energy systems since energy professionals operate around-the-clock and have backup systems readily available. Most district energy systems operate at a reliability rate of 99.999 percent, according to the International District Energy Association.
What is combined heat and power?
Combined heat and power, sometimes called cogeneration, is a way to increase the efficiency of power plants while reducing the amount of energy wasted when released into the environment. Traditional power plants use around 40 percent of the fuel they burn to produce electricity. The remaining 60 percent ends up as waste heat rejected into the environment through smokestacks and cooling towers or pumped into waterways. Combined heat and power captures this so-called waste energy to heat buildings in a nearby area through a district energy system. Combined heat and power is best utilized when there is an area near the plant – such as office towers, a campus or an industrial development – that has a need for the heat.
Solar Thermal HVAC
Can a solar water heating system be used in place of a traditional gas or electric heating system?
To ensure maximum efficiency of a water heating system, a solar energy system is usually used in conjunction with a traditional gas or electric heating system, rather than as a replacement. While it is possible to engineer a system to provide 100% of needs, the most cost-effective method is to build a system sized to provide most of the hot water, most of the time.
Do solar thermal systems produce hot water in the winter?
Solar thermal systems will function and produce hot water during winter months but may require anti-freeze protection.
Do solar thermal systems still produce hot water on a cloudy/overcast day?
Solar thermal systems can provide water heating during cloudy or overcast days, but may require traditional gas or electric heating system to achieve and maintain required temperatures.
Can I use a solar collector with my existing hot water system?
Solar collectors can usually be used with existing systems by utilizing a conversion valve that connects to existing hot water storage tanks.
What is the life of the solar collector systems?
Our solar thermal systems have a life expectancy of greater than 20 years with a manufacturer's warranty of 10 years.
Do solar heating systems require any maintenance?
Maintenance of the system is negligible. Annual assessments by Potentia maintain efficiency levels and help avoid potential problems.
