Net Zero Energy Technologies

Passive Solar

Passive solar is based on the intelligent design of buildings and takes into consideration the location of the sun to the south in relation to the placement of windows, insulation, trees and shade. A building can be more than a simple container to hold people and items. If properly designed, it can also be an engine driven by the sun that eliminates much of the external energy needs. Passive solar falls into two general applications.

• Building heating - Passive solar design of a building allows the natural capture of the sun's race by south facing windows during the winter, and window shading during the summer, and thermal mass (such as concrete and brick) to hold the heat and moderate the building's temperature.
• Daylighting - Buildings can reduce their energy loads substantially by using natural daylighting. Innovative designs out of Europe and Japan show how even the largest buildings can introduce daylight in to the deepest recesses.

Solar Domestic Hot Water
Solar energy can heat water for at least four different applications:

• potable (drinking) and service use (washing) use in homes
• potable and service use in commercial, and institutional and industrial facilities
• radiant floor heating
• swimming pools (indoor or outdoor).

Almost all applications use collectors, which are aimed at the sun to collect as much radiation heat as possible. There are three basic types of collectors:

• seasonal collectors (these units are simple design and often circulate water through plastic pipes, they offer little protection from freezing)
• flat plate collectors (these units may circulate an anti-freeze fluid through insulated pipes, and release the collected heat through the use of a heat exchanger)
• evacuated tube collectors (these are highly insulated glass cylinders which maximize the absorption of heat and minimize the loss of heat from the system).

Generally speaking, the three types above offer increasing collection efficiency and increasing cost of installation.

The number of collectors required for a site depends on a number of factors, such as the size of your load (ie: how much water do you need to heat), the efficiency of the unit, the amount of solar radiation at the site, the amount of storage available, etc.

Collectors should be aimed as south as possible, and installations require unobstructed access to the sun's path in all four seasons. Systems can be designed to provide 100 percent of your water heating or to use the solar energy as a supplement to a conventional heating facility.

Solar Electricity (Photovolataics)

Solar electric modules (called photovoltaic or PV) can generate electricity for a range of applications:

• marine and aviation navigation lights, water pumping,
• telecommunication repeater stations, oil and gas SCADA systems,
• off-grid remote houses, off-grid lodges for fishing, hunting, and eco-tourism, on-grid 'distributed generation' to reduce peak power loads, save on utility
• bills, reduce stress on distribution lines, and provide voltage support for distribution lines.

Solar PV technologies convert sunlight to electricity, as compared to active solar collectors (which convert sunlight to heat). The efficiency of solar PV increases in colder temperatures and is particularly well-suited for Canada's climate. A number of technologies are available which offer different solar conversion efficiencies and pricing.

Solar PV modules can be grouped together as an array of series and parallel connected modules to provide any level of power requirements, from mere watts (W) to kilowatt (kW) and megawatt (MW) size.

GeoExchange Technology

GeoExchange™ technology, also known as ground-source, geothermal heat pump, earth energy, etc., opens exciting new ways to capture and deliver quality thermal energy to consumers while more efficiently utilizing already-built electricity infrastructure and well-known technology.

All geoexchange systems involve a heat-transfer fluid moving within a loop to transfer thermal energy, to heat and cool spaces or processes. GeoExchange™ systems capitalize on this transfer of existing energy from earth, processes, or buildings rather than use combustion, to deliver ultra-high efficiencies and renewable heating and cooling.

Under national design and installation standard CSA C-448, geoexchange systems operate at a minimum COP of 3.0, or approximately a 300% minimum efficiency. This means that for every unit of electricity invested in to a system, at least two units of 'free' heat or cool are transferred from the earth.

For example, when geoexchange meets 100% of heating needs, it saves as much as 70%, compared to electric resistance heating. When cooling a space, given the naturally low temperature of the earth, GeoExchange™ usually operates about 35% more efficiently than even EnergyStar-rated air-conditioning technology.

In some applications efficiencies as high as 800% can be achieved when parts of a building require cooling at the same time that others require heat. Well-designed GeoExchange™ systems often can achieve higher technical and economic efficiencies with integrated low-temperature hydronic systems, or thermal storage tools such as hot water or ice tanks.

Compared to non-electric heating systems such as gas or oil, geoexchange systems will add a steady, small amount of electric demand to the winter grid. Often, stakeholders believe that adding any electric demand is a pure negative. This perspective ignores however an important property of electricity and price: its time of use. When thermal storage media - cement floor hydronic systems, water tanks, or more complex systems - are integrated, heating and cooling can be done partly or entirely off-peak. GeoExchange™ systems can therefore be part of an electricity strategy to more fully utilize existing electricity infrastructure, and help better control peaks. GeoExchange™ technology's flexibility can therefore add flexibility to electricity supply infrastructure and help manage system risk.

(Source: Canadian GeoExchange Coalition)