By Tim Van Seters, Amir Safa and Dr. Alan Fung

Heat pumps are among the most energy efficient technologies for heating and cooling buildings and providing hot water. They function by moving heat from one place to another. Usually the ground or air acts as the source and sink for heat, and since energy from these sources is free, the only energy needed is the electricity required to operate the heat pump and forced air or hydronics distribution systems.

In recent years, improvements in the operation and efficiency of heat pumps have prompted leaders in the residential construction sector to take a second look at these technologies. The first question, of course, is how well they perform in cold Canadian climates. This was what we set out to understand through a one year monitoring program conducted with researchers from Ryerson University. The heat pumps evaluated were installed in two, comprehensively monitored, semi-detached LEED™ platinum demonstration houses owned and operated by Toronto and Region Conservation at the Living City Campus in Vaughan, Ontario.

Although not identical, the two houses, referred to as House A and House B, have similar floor areas, internal volumes, and levels of insulation. House A has a 10.5 kW (3 ton) high efficiency variable capacity air-to-air source heat pump manufactured by Mitsibushi™. It includes a direct expansion coil air handling unit (AHU) and a multi-speed fan to supply warm and cold air for space heating and cooling. The system is coupled with a mini-boiler, which was not needed over the period of study because the ASHP alone was able to supply sufficient heat, even during cold periods down to -22°C.

The main heating and cooling system in House B is a 13.3 kW high efficiency ground source heat pump (GSHP) manufactured by WaterFurnace™. It is coupled with two 152 m (500 ft) horizontal loops in the yard. The installation uses a buffer tank to store water, which is then distributed to an in-floor radiant heating system during the winter, and through the zoned air handler for cooling the house

Data for the study were collected year round and a energy performance model (TRNSYS) was calibrated to simulate energy performance over the entire heating (October 1 to May 21) and cooling seasons (May 22 to September 30) based on climate normals derived from a 30-year historical record of solar irradiance and temperature.

Results of the evaluation showed the heat pumps to have performed very well with heating and cooling efficiencies above both Energuide and manufacturer rated performance (Table 1). During the heating season, both systems had coefficients of performance (COP) above 3, indicating that the systems provided over 3 kWh of output heat for each kWh of energy consumed. During the cooling season, COPs were 5, and Seasonal Energy Efficiency Ratios were well above rated performance levels.

These ratings are based on the performance of the heat pump systems without the forced air and hydronics distribution system specific to each house. Overall ‘as installed’ performance declined dramatically when the electricity consumed by the distribution systems was included in the assessment. As shown in Table 1, cooling season COPs for both systems fell by more than 30%. During the heating season, the ASHP system suffered a more significant decline because the air handling unit used with the ASHP consumed much more electricity than the water pump used with the GHSP.

Further investigations showed that the high electricity draw by the distribution systems was caused, in part, by the way in which the units were being operated. Simulating these during the cooling season to operate only when the heat pump and compressors were on caused a reduction in electricity consumption of between 28 and 37%. The difference between ‘stand alone’ and ‘as installed performance’ highlights the importance of understanding the various components that make up the system, including HEPA filters and heat recovery ventilators, and ensuring these are optimally configured to maintain high levels of efficiency and energy performance.

It was surprising that the ASHP performed almost as well as the GHSP given that the ground maintains a much more constant temperature than air. The effect of source temperatures on performance was evident in the COP data. While the GSHP maintained a relatively constant COP of roughly 3 regardless of outdoor temperatures, the COP of the ASHP declined from 4.9 to 1.6 as outdoor temperatures fell from 9 to minus 19˚C during the winter. Below minus 24 ˚C, the ASHP was less efficient than a conventional electric heating system, and a supplementary heat source would be required (Figure 1).

Part of the explanation for the impressive ASHP performance lies in its capacity to vary the speed of the compressor. At temperatures warmer than minus 15˚C, the variable capacity ASHP compressor operated on part load, drawing less than half the electricity (2 – 3 kW) required under full load conditions (6 kW). Only when outdoor temperatures dropped below minus 15˚C did the ASHP compressor switch to full load. Heat pumps that operate on full load only are less efficient because, compared to variable capacity systems, they cycle on and off more, and provide less overall heat output per unit of electricity consumed.

We see this with the GSHP, which only had the capacity to operate at full load, causing the compressor to cycle on and off much more often than the ASHP compressor. During the cooling season test period, for instance, the compressor operated between 1 and 7 hours and cycled on and off up to 25 times a day. Over the same period, the ASHP variable capacity compressor operated between 3 and 11 hours per day and turned on and off only once. This cycling not only reduces energy efficiency, but also wears down the equipment and adversely affects thermal comfort.

Simulations of performance in 5 major cities – Halifax, Montreal, Toronto, Edmonton and Vancouver -showed that both systems would function well. As expected, however, performance of the ASHP was more sensitive to differences in air temperature. In Montreal and Edmonton, for instance, the ASHP had lower COPs than other cities. These would be further reduced if supplementary heat at the coldest temperatures was included. In Vancouver, the warmer and more even year round temperatures resulted in higher ASHP performance. During the cooling season, the GSHP system slightly outperformed the ASHP in all cities, with COPs ranging between 5.8 and 6.1.

Ultimately, the equipment choice will be largely motivated by cost and energy savings. Based on monitoring data collected in this assessment, the ASHP was found to be more affordable overall. Significant savings are associated with not having to install a ground loop. Also, long term performance of the ASHP is not contingent on ensuring that heating and cooling loads are in balance. If life cycle costs and benefits are considered, the price gap may narrow because the ground loop is a one time cost and the GSHP compressor is subject to fewer mechanical and thermal stresses (since it is indoors) with a longer expected service life. Natural gas furnaces are currently more cost competitive at the residential scale, but as gas prices creep up again, we may see more heat pump systems in city neighbourhoods.

Tim Van Seters manages Toronto and Region Conservation’s Sustainable Technologies Evaluation Program. He oversees a team of research scientists and technical experts engaged in scientific evaluations of green energy and clean water technologies. For more Information contact tvanseters@trca.on.ca

Amir Safa and Dr. Alan Fung were the lead researchers from Ryerson University’s Department of Mechanical and Industrial Engineering. Contact Information: alanfung@ryerson.ca

Table 1: ASHP and GSHP Performance. Manufacturer and Energuide ratings apply to ‘stand alone’ system. The ‘as installed’ system includes the electricity consumed by the AHU and hydronics distribution systems

Quantum Geothermal goes the extra mile to provide quality geothermal solutions for homes

By Greg McMillan

Brian Bates of Quantum Geothermal has never been one to walk away from challenges – in fact, he embraces them.

As owner and founder of a southern Ontario company that provides quality geothermal solutions for homes, he takes pride in making sure each system is designed to the specific needs of customers to insure the best value and performance.

“I particularly enjoy working on custom-designed new build residential projects, where unique architecture may require a more sophisticated heating and cooling solution,” says Bates, P. Eng., who graduated from the University of Waterloo with a B.A.Sc. in mechanical engineering. “These more challenging projects are very satisfying. You have a chance to establish a relationship with the architect, builder and clients. It takes months to complete a project but we can really bring value to the outcome.”
Quantum Geothermal, founded in 2009, has a mandate to be a full-service operation, working in all areas of geothermal. By focusing exclusively on residential geothermal projects – both retrofit and new build projects – the company has developed a competitive skill set and highly efficient business model.

“I reach out to architects and builders,” Bates explains. “I host information seminars and visit architectural firms to meet and discuss ways to optimize the integration of geothermal heating and cooling systems into the project at an early stage in the design process.

”This initiative has allowed Quantum to develop some degree of repeat business with participating firms. Residual income or generating repeat business is a problem with our geothermal business model since the life cycle is very long. With residential installations, particularly, there is virtually no maintenance (or spare parts) required.

”By developing relationships with other stakeholders, however, it helps to address this business issue.”

From day one, Quantum has gone that extra mile.

“A friend of mine who is a custom home builder was looking to expand his use of geothermal heating and cooling systems for some of his projects in the west GTA but had become discouraged by the lack of professionalism and quality of service from some of the geothermal contractors he had approached,” recalls Bates. “From there, a process of investigation and due diligence followed, leading to the conclusion that there was a need and an opportunity. He helped me assemble a team of experienced and well-respected partners.

”Next I spoke to all the reputable equipment suppliers in Ontario to determine which brand of heat pumps Quantum would represent. “
He says this led to Quantum’s designation as an authorized dealer for NextEnergy from Elmira, Ontario. Bates noted that NextEnergy represents the ClimateMaster product line manufactured in the United States and is also expanding its commercial presence by offering both ClimateMaster and Viessmann heat pumps.

With hundreds of successful projects completed and an impressive list of satisfied customers, Quantum’s reputation for cost competitive, quality installations continues to grow. In fact, Quantum has recently received a National Award and has been recognized for its growth and professional commitment. Bates says the company takes an intelligent, honest and personalized approach as it continues to grow the business and expand the use of geothermal heating and cooling systems in southern Ontario.

“The retrofit market has always contributed to our bottom line but the pace is different,” Bates explains. “We get the crew onsite to excavate for a day or two (or drill vertically for a few days) and then spend a day down in the basement replacing the old furnace with a new heat pump. Done … then move on.”

The public, Bates says, has been extremely receptive to Quantum’s product, which has a cost- competitive model and offers a quality solution to a variety of client requirements.

“But there is still an urgent need to continue to advocate for this technology,” Bates says.
“Often the first question I get when we receive a new inquiry is ‘how much will it cost?’

“I understand that, but it misses the mark in terms of thought process. That is like phoning up a car dealership and asking ‘what does a car cost?’
“That is why we developed our own Energy Evaluation survey on our website. People need to understand that there is a process involved that is essential to constructing an energy-efficient and cost-effective geothermal heating and cooling system. There is science and guidelines and regulations and knowledge and client-specific information required.
To that end, Quantum can provide builders with a comprehensive report describing its scope of work, so they know exactly what skills and services are in the mix.
Looking ahead, Bates sees more challenges for Quantum and, again, he relishes the opportunity to confront them head on.

“Generating sales is an ongoing challenge for most small businesses and Quantum is no different,” he says. “Marketing, advocating for geothermal and continuing to reach out to architects and builders will be critical to our continued success.
“But particularly in the construction of new homes, I see geothermal being specified right from the concept and design phase with ever-increasing regularity. This is very encouraging and sustains our belief that our efforts are being recognized.”

Web:  HYPERLINK “http://www.quantumgeothermal.com/” \o “This external link will open in a new window” \t “_blank” http://www.quantumgeothermal.com/

A key part of Quantum Geothermal marketing is done through the  HYPERLINK “http://www.quantumgeothermal.com/” company website where there are links to associated government and industry sources. Visitors can also complete Quantum Thermal’s Energy Evaluation survey, or watch a three-minute video for a quick company overview. Geothermal is well-established and will continue to grow as a viable, renewable energy alternative to fossil fuels. Advocacy and education are keys to accelerating the curve.