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INTRODUCING THE LOW TEMPTERTURE HEAT PUMP

Heat pumps are expensive where outdoor temperatures approach freezing. But David Shaw, a retired refrigeration engineer, believes the market could soon be ripe for a low-temperature air-source heat-pump (LTHP) he is developing. The difference between a conventional heat pump and the LTHP is the addition of a second "booster" compressor and a "subcooling economizer". In Stage 1 mode, the booster compressor activates when the outside temperature reaches 25°F. The extra capacity allows more low-density refrigerant to be compressed into the liquid required to bring heat to the interior of the building. In Stage 2, the economizer kicks in. It uses wasted heat to produce refrigerant vapor sent directly to the primary compressor, instead of into the evaporator coil. When developing the LTHP, Shaw knew that in most heat pumps, even after the liquid refrigerant has given up much of its heat to the condenser, it is still pretty warm. When it's cold outside, this warmth causes as much as 40 percent of that liquid to vaporize as it goes through the expansion valve. If it was cooled first, more of the refrigerant would remain in liquid form, so it could be boiled later in the evaporator coil, where it absorbs heat from the outside air while changing states. Shaw figured that one way to cool the refrigerant would be to "donate" some of its surplus heat to a process that would create a source of high-density vapor that would bypass the evaporator coil altogether and be sent directly to the primary compressor. Shaw's LTHP uses sensors and controllers to sequence different components at the proper time. Energy is never used to supply excess capacity to the system. The payback for installing a LTHP differs by region as well as costs for fossil fuels, electric rates, and weather conditions. Often, both furnaces and water heaters must be changed to electric to make the numbers work.
Architectural Record, Mar 06, p 123, by Charles Linn.

EXHIBIT EXPLORES LINK BETWEEN SUSTAINABLE DESIGN AND VERNACULAR ARCHITECTURE

A recently opened Canadian exhibit presents a unique exploration into the constantly evolving area of sustainable architecture. Entitled, 41° to 66°, Regional Responses to Sustainable Architecture in Canada, the exhibit addresses the link between contemporary projects incorporating sustainable design with regional vernacular architecture across Canada. It is curated by University of Waterloo Associate Professor John McMinn and Ryerson University Associate Professor Marco Polo and includes projects from six cultural and geographic regions of Canada: Arctic, West Coast, Mountain, Prairie, Continental and Atlantic. The curators believe architecture can play both a practical and symbolic role in our culture. But until recently, sustainable architecture has been disconnected from the broader culture by being discussed only through the lenses of technology and energy performance. In their exhibit, Polo and McMinn sought to explore this disconnect while forging an argument for reconnecting sustainability to the larger critical discourse of contemporary architecture. McMinn says he views the Nicola Valley Institute of Technology building as a poster child for the show because it hits upon his and Polo's argument in many ways. "It is a green building but not a perfect green building. The way it approaches a cultural response is interesting: it addresses a specific client and a micro-region." The exhibit most recently appeared at the Cambridge Galleries in Ontario, and will be traveling across Canada. Details on locations will appear in Canadian Architect.

LESSONS LEARNED FROM COMMISSIONING GREEN BUILDINGS

CTG Engineering, Inc., which has served as the commissioning authority for 10 LEED New Construction buildings and is currently commissioning about 20 additional projects pursuing LEED certification, offers five anecdotal lessons learned from their experience: 1) Owner commitment is key. Commissioning sometimes is seen as an impediment to achieving LEED certification because it is one of the last activities prior to submitting a LEED application. Toward the end of construction, when much commissioning-related testing occurs, it can be easy for owners to focus on completing construction and submitting the LEED application quickly, while avoiding activities that result in additional costs. 2) Avoid unmanageable complexity in building systems. The same enthusiasm that leads owners and designers to strive for greener buildings can cloud professional judgment and result in system designs that are untested, difficult to construct and beyond the comprehension of building occupants and operators. 3) Sequences of operation often are ambiguous. Incomplete and ambiguously written sequences of operation by designers or installers make it difficult for a commissioning agent to develop testing procedures. Design teams should issue a detailed written sequence of operation for each active system and a controls contractor should prepare "red lines" highlighting changes made during programming, startup, testing and fine tuning of systems. 4) Daylight dimming systems require significant coordination. Greatest success with lighting controls occurs when lighting designers, installing contractors, manufacturers' representatives and building operations staff work together in the field to tune the location and calibration of controls. 5) Underfloor air distribution (UFAD) requires careful coordination of trades. The project team should pay close attention to supply-air-plenum leakage both in the design details and field installation. Operating UFAD systems with constant air volumes or only limited variations in supply-air volume is more successful than using control strategies employed in conventional overhead VAV systems. UFAD systems based on changes in space temperature are more successful than those that use plenum pressure as a key control variable.
HPAC Engineering, Feb 06, p 24, by Erik Ring and Jerry Ingwalson.

PHILADELPHIA PLUMBERS UNION SAYS NO WAY TO NO-FLUSH URINALS

The local plumbers union is blocking Liberty Property Trust's plan to install no-flush, water-saving urinals in the men's rooms at the Comcast Center in Philadelphia. Without them, the 57-story skyscraper would guzzle an extra 1.6 million gallons of water a year. It also could have trouble obtaining U.S. Green Building Council certification and beating out Manhattan's Bank of America Tower as the nation's tallest green building. Those involved in the urinal debate say the plumbers object to the waterless devices because they require less labor to install than the traditional kind. The city's building code has no provision for waterless urinals. And because the plumbers are so opposed to the technology, Philadelphia officials are reluctant to introduce its use in the city. "We're still looking into this. I want to make sure they're safe," said Robert D. Solvibile Sr., who runs Philadelphia's Department of Licenses and Inspections, the agency that enforces the city's building code. "We're afraid that if they're not properly maintained, dangerous gases could come into the room and harm people." "Dangerous?" laughed Douglas Durst, developer of the Bank of America Tower, when told of Solvibile's concerns. "We've had them in our offices for four years. If they're dangerous, we haven't noticed." Ironically, the Philadelphia Water Department has been looking for ways to reduce the water flowing into the city's overburdened sewer system. After a heavy rain, the city must often release untreated sewage into the Delaware River. "Waterless urinals would certainly be in line with our sustainable goals," said Glenn Abrams, the department's urban watersheds planner.
The Philadelphia Inquirer, 19 Mar 06, by Inga Saffron.

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