Our Green Achievements
Our priority, since we started the company in the mid-80s, has been cost-effective energy management. We use the latest proven technologies and we have been leading the industry in energy-efficient retrofits since the late 80’s.
- We were pioneers in the design of a district heating system (Meadowvale II 1991)
- Lead the way in applying variable speed drives to booster pumps (Palace Pier – 1996)
- Designed an all variable speed/variable flow chiller plant (Palace Pier 2002)
- Engineered a air-to-air heat recovery system for a multi-res building (Longview Housing Co-operative – 1998),
and;
- Conducted research for CMHC into the proper application of fan-assisted boilers.
The PST System:
A More Efficient Way of Piping
The PST system is a more energy-efficient way to pipe a boiler plant. It was adapted by Fred Weinstein in the early ‘90’s from large scale campus heating plants used to heat multiple buildings.
How does it work? Simply. On our little model, the boilers in the background send hot water into the white boiler loop. This loop holds enough water to prevent the boilers from rapid cycling.
Heat from the boiler loop is pumped through the purple injection circuit into the green heating distribution circuits. The amount of how water injected is controlled by variable speed injection pumps or motorized 4-way valves. The temperature control is very precise – to within a degree. Cold water coming back from the distribution zones is mixed with hot water in the white boiler loop before being returned to the boilers. The blue cube near the boilers represents a double-wall plate heat exchanger. Heat is transferred from the piping attached to the boiler loop to the domestic hot water which is pumped into the gray domestic hot water storage tank.
The PST system has a number of advantages:
- The send-out temperatures can be very low, lower than 38ºC (100 °F), without risking having low return water temperatures damage the boilers. This eliminates overheating, particularly in buildings with baseboard convectors, radiators or radiant heating.
- Each zone has its own individual temperature settings.
- There is enough water in the boiler loop to ensure that the boilers do not rapid cycle – which saves energy and reduces wear and tear on the boilers.
- Domestic hot water can be heated from the main boiler plant, often without increasing the boiler capacity because the peak load for heating does not happen at the same time as the peak load for domestic hot water.
The PST system has been copied by many designers (which we encourage) and is now known by many as an ‘injection’ system.
Toanche Building:
Radiant Heating and Cooling
The Toanche building is on the Penetanquishene Mental Health Campus. It was a ‘green’ building when it was built in the early ‘70’s. It used ‘pulse’ condensing boilers and radiant ceiling panels for heating. In the intervening years, conventional fire-tube boilers replaced the original condensing boilers. Of course, these boilers work on a much higher temperature regime, resulting in uncomfortable overheating and rapid cycling of the boilers.
Our assignment was to correct the overheating and to prevent the rapid cycling of the boilers. We did that by revising the piping and pumping to the PST (primary-secondary-tertiary) system. This system keeps the boilers at the high temperatures that they need for long life, while each of the 16 zones could have individual temperature control at much lower temperatures – generally around 43ºC (110°F).
When we were asked to add air conditioning and improved ventilation to the system, we decided to use the existing radiant ceiling panels. A Smardt TurboCore oil-free chiller was installed with a remote air cooled condenser. This is the most energy-efficient chiller on the market. The moving parts revolve in an electro-magnetic field; there are no conventional bearings, no oil and no friction. In addition, each of the 3 compressors has an integrated variable speed drive for very good low load performance. The chilled water is sent to the radiant panels for gentle sensible cooling.
A new rooftop air handler contained a heat recovery coil, recovering heat from the building exhaust in the winter, a pre-heat coil, a main heating coil, a cooling coil, and a reheat coil. This unit sent de-humidified air to each room in the building through VAV boxes. A 200 point Carrier control system controlled the amount of fresh air received by each room and controlled the dew point at the ceiling panels.
This system does not re-circulate air within the building, which is important in a hospital to not only lower the energy consumption but to help prevent germs from circulating through the building.
Granite Place:
Two Buildings, One Chiller Plant
Granite Place is composed of two condominium towers joined by a common reception and lobby. There were originally two chiller plants totaling 720 tons of cooling. The condenser water pumps were grossly oversized, totaling 65 HP. The chilled water pumps were also oversized, totaling 140 HP.
We piped the two buildings together and used a single chiller plant to replace the two former plants. After doing the cooling load calculations and simulating the building energy consumption, we determined that the chiller capacity could be reduced to 400 tons and the total pumping power for the condenser pumps to 2x15HP and the evaporator pumps to 2x20 HP. We also abandoned the two cooling towers on one of the buildings. All pumps were controlled by variable speed drives. In total, over 34 kW of electrical demand was eliminated.
We selected a Smardt chiller with a CPECS chiller plant optimization panel. The Smardt chiller is widely recognized as the most energy efficient chiller on the market. It also features the reliability of multiple compressors. Each of the 4 compressors is controlled by an integrated variable speed drive, so it can operate efficiently at very low loads. This is necessary because this chiller plant operates all year round. The CPECS panel controls all of the variable speed drives on the condenser and evaporator pumps as well as the cooling tower fans. It uses unique algorithms to coordinate all aspects of the chiller plant to achieve the best overall energy-efficiency. This chiller plant qualified for over $100,000 in rebates and will have a simple payback of less than 10 years.
80 & 100 Quebec Ave:
Two Buildings, One Chiller Plant, No Water Consumption
Like Granite Place, this project had 2 condominium towers, each with their own chiller plant. We piped the buildings together through the parking garage and installed a single chiller plant to serve both buildings. In this case, a Smardt chiller with 4 TurboCore compressors and a remote air-cooled condenser was used. This chiller plant uses no water, which will save over $18,000 per year. (The cost of water is significant – most chiller plants evaporate about 43 gallons per day per ton of cooling. So a 360 ton chiller will use about 1.8 million gallons. In Toronto, the 2011 cost of water is $0.0104 per gallon) Because it is a closed system, chemical treatment is not required. Maintenance costs are lower because there is no open tower and condenser water to clean.
This plant demonstrates that ‘green’ can also be cost effective.