High-performance building approach to condos

Modelling software helps determine optimum performance throughout a building's life cycle
Friday, February 3, 2012
By Scott Lenger

Canadians have more than price, location and amenities on their minds when shopping for a new or existing condominium unit. The vast majority also want to live in a building that is environmentally friendly and energy-efficient.

This comes as no surprise to condo developers, building managers and association boards who understand the appeal of a green building. Many of the highrise condos built over the last decade make use of design features and technologies that reduce both energy consumption and greenhouse gas emissions.

In recent years, environmental regulations, new innovations and higher energy costs have raised the bar on green buildings and provided economic incentives for developers, building managers and boards to embrace a high-performance building approach for both new construction and existing condo developments.

High performance buildings focus on life cycle performance
Today’s best-in-class high-performance buildings are designed and operated to meet specific standards for energy and water use, system reliability and uptime, environmental compliance and occupant comfort, safety and productivity. They use performance standards that are created, measured and continually validated to deliver established outcomes within specified tolerances.

The costs of operating a building over its decades-long occupied life typically represent between 60 and 85 per cent of total building life cycle costs, according to the International Facilities Management Association (IFMA). The small incremental cost – estimated at between one and 6.5 per cent – of designing and constructing a high-performance building is offset many times over by energy and operating efficiencies that can deliver between 20 and 50 per cent annual savings compared to conventional buildings.

Using sophisticated energy and building modelling software, design teams can analyze various HVAC technologies and other building systems to determine which options will deliver optimum performance throughout the building’s occupied life.

Modelling techniques use actual building characteristics to accurately simulate the impact of various energy conservation measures. For example, modelling takes into account the effect energy-efficient lighting, windows and roofing materials have on heating and cooling requirements, often enabling designers to specify smaller, more efficient HVAC systems.

The design team can also run computer simulations that compare the energy efficiency and performance of a conventional heat pump to those of a geothermal heat pump. A geothermal heat pump uses the relatively constant temperature of the earth as a heat source in winter and a heat sink to absorb heat in summer.

Recent advances in piping technology have made geothermal systems more affordable in terms of constructability. Geothermal systems also use less energy and produce fewer carbon emissions than the conventional heat pumps used in most modern condo units, making them a viable option for many high performance condo building applications.

Central plant systems offer potential savings opportunities
Individual HVAC systems for each unit have been the default choice for highrise condo buildings for decades. But a large central heating and cooling system is almost always more energy-efficient and has a smaller environmental footprint than the combination of many smaller systems, each with its own compressor unit.

The challenge of allocating costs to individual condo owners based on their energy use has largely been overcome thanks to innovations in metering technology, which give building managers the usage information they need to bill individual owners for the energy they use.

In many cases, it makes sense for condo developers to consider equipping new buildings with an advanced central four-pipe chilled water system, which provides the optimal blend of low long-term cost and high owner comfort and flexibility. Four-pipe chilled water systems are capable of providing heat to one condo unit and cooling another, which is particularly important during the change of seasons.

Use of a central plant design offers developers the ability to recover heat from the chilled water system, which can be used to preheat domestic water, reducing energy consumption. Recovered heat from the system can also be used for other purposes such as heating swimming pools, especially during the high cooling season.

In addition, during the mild days of spring or fall, the chilled water system can be configured and programmed to operate in a “free cooling” mode, economically cooling and circulating outdoor air without running system compressors.

HVAC advancements improve performance of existing buildings
Many of the energy conservation measures that should be considered in new building design also apply to existing condo developments. The right mix of high-performance building technologies and practices can improve building performance and reduce energy consumption by as much as 40 per cent, according to research analyzed by the National Research Council Canada (NRCC).

Energy audits are valuable tools for assessing current levels of building performance, comparing current performance to best-in-class buildings and identifying improvement opportunities. Building managers and condo boards often engage energy service companies to conduct an energy audit and identify, prioritize and implement energy conservation measures. A critical systems audit can help building managers identify and address building system issues before they can become serious problems.

Upgrading older HVAC systems with new, more energy-efficient technology is often a good investment over time. The retrofit process also gives managers the opportunity to reduce the size of their HVAC systems to take advantage of technology improvements. In addition, an energy audit sometimes reveals the original system is larger than necessary, due to incorrect assumptions made when it was specified.

An effective maintenance strategy is a key element of any high-performance building strategy, for both new and existing condo developments. A maintenance program that is predictive and data driven can dramatically improve system reliability and reduce operating costs over a condo building’s long occupied life.

Building automation systems and other innovative technologies provide building managers with the information they need to service equipment when service is needed, not just at scheduled intervals. Today’s intelligent service offerings use advanced sensors and microprocessors that enable continuous monitoring and fault detection. These capabilities give facilities professionals the actionable data to predict and, in many cases, prevent failures before they happen.

Scott Lenger is responsible for managing strategic relationships for Trane, a leading global provider of indoor comfort systems and services.

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