Energy modeling: Get the best HVAC system for your building
Vernon resort leans on leading-edge HVAC system, but it's not for everyone
Sparkling Hill Resort is perched high on a hillside overlooking Lake Okanagan in Vernon. It has more than 3.5 million Swarovski crystals scattered throughout its soaring lobby, health spa and 152 guestrooms.
But it's not all about glitter.
The resort is also highly energy efficient, relying on a ground source heat pump/fan coil system for heating and cooling. The state-of-the-art hybrid system reduces heating energy consumption by 39% and its cooling energy consumption by 14.2% over a comparable building with a traditional HVAC system.
With such terrific energy savings potential, the latest energy-efficient HVAC systems are tempting. But, according to BC Hydro energy management engineer Tao Jiang, new technology is not always the best fit.
"It's not good to blindly adopt the latest thing for your new building," says Jiang. "It may be sexy new stuff and great technology, but not all technology is suitable for all projects."
Below, we'll take a look at:
- Which new HVAC technologies are available;
- How energy modeling is used to investigate what will be the best system for a commercial building;
- How BC Hydro's New Construction Program can cover up to 100% of the cost of energy modeling and provide incentives for installation of energy-conservation measures.
Ground source heat pumps and air source variable refrigerant flow (VRF) systems are relatively new here but have been used in Europe and Asia for years. Half of all medium-size buildings in Japan currently use VRF systems.
In winter, a ground source heat pump (also known as a geothermal heat pump) extracts heat either from the earth beneath the frost line or from a body of water and transfers it to the building for heating. It then reverses the process to cool the building in summer.
It's very energy efficient, but the building site must be suitable for a ground source heat pump to work at its best: the ground conditions be right, and the building itself should require close to equal amounts of heating and cooling throughout the year.
If the heat extracted from the ground cannot be compensated for by the waste heat from the building or adjacent ground, the balance will be off and the building will most likely require an additional heating source – reducing or eliminating energy savings.
Likewise for a VRF system. This kind of system can modulate the output of an outdoor unit and share heat between multiple heating and cooling zones by transferring wasted heat from indoor units in cooling mode to spaces requiring heating. But for it to work at optimum efficiency, zoning must be carefully and accurately planned based on space heating and cooling loads.
"For the right project, like the 3383 Gilmore building in Burnaby, a VRF system can provide the ultimate in energy conservation," says Jiang.
The five-level office tower in Burnaby's Discovery Place Research Park, now leased by HSBC, achieved LEED Platinum standard in part by installing an air-source VRF system that reduces electricity consumption about 34% over a conventional HVAC system.
"Here, the design team picked this system based on a detailed energy modeling study that enabled them to plan out the zoning properly and make the best use of the system."
Energy modeling: getting it right
Whole-year simulations can predict how a building will perform
The best way to find out what systems are the best match for any new commercial building, no matter its type or location, is energy modeling.
"Modeling programs can run whole-year detailed simulations to show how a particular building will perform at different times of day and night, and in different climates," says BC Hydro specialist engineer Bojan Andjelkovic. "By doing this at the early concept design stage, you can interactively explore different design strategies.
"You can see, for example, what happens if you change a building's orientation, shape, mass or envelope, or if you use different building systems and energy sources. It's much more time- and cost-effective than trying to make changes later."
Energy modeling helped St. Mary's Hospital in Sechelt opt for a range of energy-conservation measures.
First built in 1963 and last renovated more than 20 years ago, St. Mary's was fast becoming too small and too out-of-date for the Sunshine Coast's growing population. Now, the new hospital is a showcase of the latest in safe patient care. And its passive energy-saving measures – such as high-performance glazing and solar shading – help to reduce St. Mary's energy consumption by 33% a year.
How BC Hydro's New Construction Program can help
Jiang says energy modeling uses variables – from the size of windows to the selection of wall materials, systems and the number of people in a building – to predict a building's energy use.
And in all three of the energy-efficient projects described in this story – Sparkling Hills, the Discovery Place Office Tower and St. Mary's Hospital – BC Hydro's New Construction Program played a major role.
"All these buildings went through BC Hydro's New Construction Program," he says. "We cover up to 100% of the cost of having a professional energy modeler complete a simulation, and also provide really good incentives to install energy-conservation measures.
Jiang recommends energy modeling as a great design tool that allows a team of architects, mechanical and lighting consultants to work together.
"Energy modeling allows them to test out their ideas and avoid the situation where they suddenly realize the equipment is efficient, but the design is faulty," he says. "They can also demonstrate to their clients why they are recommending one system or solution over another, and the owners then have the benefit of long-term operational savings on their energy use. Everyone wins."
Find out more about energy modeling and BC Hydro's New Construction Program online or call 1 866 522 4713.