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HEATING CONTROLS UPGRADES IMPROVE TENANT SATISFACTION, EARN 2-MONTH PAYBACK
EUN Digest - Fall, 1995 - Improvements executed to restore the efficiency of a malfunctioning perimeter heating system at the Commerce Plaza office building here not only paid for themselves through energy savings in less than two months, but also dramatically improved occupant comfort.
The 11-story, 138,815 square-foot building is owned by Sakto Development Corp. and managed by Royal Le Page Real Estate Services Ltd. When the all-electric facility was constructed in 1989, the owners specified a radiant resistance perimeter system as the building's primary heat source, according to Dan Lynch, Royal Le Page's on-site building engineer. A PACE weather-sensitive heating system, purchased at an incremental cost of about $80,000 from General Electric Engineering Inc., Rahway, N.J., was installed by the building's HVAC contractor, he told EUN.
"This is a totally different design concept than any other heating system," Lynch claimed.
The system operates by gathering data on weather conditions on each face of the building, using an array of solar, wind, humidity, and temperature sensors. Based on input from the sensors, a supervisory stand-alone controller modulates radiant panels installed in perimeter offices. After initial programming, PACE is designed to compensate automatically for heat loss and gain. The remainder of the building's heating was expected to be provided by "computers, lights, and bodies," Lynch said, yielding an indoor temperature in the range of 72-74 degrees F.
Originally, Sakto bought PACE with the intention of cutting heating costs by 20-25 percent, according to Lynch, which would have yielded a payback on the system's cost premium in less than two years. But the return was never realized because the installing contractor improperly wired, incorrectly zoned, and erroneously calibrated the sensors, he contended. Improper installation and calibration caused the system to consume more energy, and the trouble was further compounded when previous engineering management failed to correct the problem.
"The original contractor was totally deficient and the former building engineer never really understood the system or had any luck in getting the contractor to respond to trouble calls," Lynch told EUN. "Nor did he make the building owner fully aware of the problems. When I first got here three years ago, we only had one tenant and even then, when I looked at the bills, the consumption was quite high. As the building filled up, it became extreme because our bills were going up by about $7,000-$8,000 per month. "A comparison of facility's performance with results of a survey taken about a year ago by the Building Owners and Managers Association International (BOMA) of similarly sized all-electric buildings in the area confirmed Lynch's belief that the system was not performing as well as it should. Of the 25 properties covered, Commerce Plaza had the fifth highest electricity consumption.
There was also a constant stream of "no heat" complaints from the tenants, Lynch recalled.
"The magnitude of the problem really hit home when a very influential occupant, whose lease was due, came up to me and said his company hadn't been warm in four years," he said.
"The magnitude of the problem really hit home when a very influential occupant, whose lease was due, came up to me and said his company hadn't been warm in four years," he said.
When Lynch began investigating, he found that the solar sensors, which are mounted inside the building's green-tinted glazing, should have been set for 8.5 volts output to compensate for the shading effect of the glass.
Measurements revealed that the output voltage was only at around 2.5 volts.
"The way they were set, those sensors couldn't pick up solar gain for love or money," he observed.
Furthermore, during an earlier stairwell installation project, sensor wires routed between the seventh and eighth floors were severed and the east side of the building was inadvertently reconnected to the west side sensors.
Duct and baseboard heaters had been installed to alleviate the deficient heating condition, but the effect was marginal, Lynch continued. To migrate the problem once and for all, he told the EUN that he contacted the manufacturer and worked closely with it to secure the appropriate data and parts need to totally rebuild the system.
"General Electric was not aware of the problem either," Lynch commented. "We have to give them a lot of credit for supporting us."
The improvements were completed in April 1994 at a cost of about $6,000. With a year's worth of utility bills now in hand, the effort has cut energy consumption by 849,600 kilowatt hours and lowered average monthly demand by 88.5 kilowatt (kw), resulting in annual savings of $56,829, reported Richard Leccese, an energy advisor with the local municipal distributor Ottawa Hydro. He added that savings, calculated in Canadian dollars, include a 7 percent goods and services tax of $3,178. Payback was realized in the first 1.3 months of the heating season, which usually runs from October to March.
The improvements included rewiring the solar sensors, revamping the panel calibration boards, and reconfiguring the heating zones. The panels, each rated at 45 kw, measure 1.5 feet wide by 6 feet long. Mounted overhead almost flush with the inner edge of the glass, the heaters are divided into eight zones per floor, with four panels per zone. Lynch explained that the building itself is divided into two large zones. Six solar sensors are installed on the second to control the first five stories, and another six are on the sixth floor to regulate the remaining space. Roof-mounted sensors measure wind speed and outdoor temperature. Relatively humidity is read from the air handler intake.
The PACE controller which Lynch now supervises through the building's direct digital building automation system - made by local vendor VCO Controls - consists of master and auxiliary computer boards. The master board channels sensor outputs to the auxiliary board, which controls heating panel timers and relays. While the end user can program heating on each face of the building separately, baseline parameters are set from the north-facing side because it is the coldest and receives the most wind.
Since the retrofit has been completed, tenant satisfaction has soared and the utility bill savings have allowed the property management firm to be more competitive in a down market, according to the building owner.
"Occupant comfort was a driving force behind this whole retrofit," commented Sean Murray, Sakto's owner. "Tenant satisfaction has gone from 68 to 98 percent."
Because it now has in-house expert capable of operating and calibrating the system, Royal Le Page can now devote more resources to working on other building systems, improving engineering response times, according to Mats Striegler, an executive with the company.
"The key to this whole industry is a strong on-site connection between the tenant, the property manager, and the owner," Lynched observed.
He noted that lower operating costs give the building an edge in an increasingly competitive market.
"The market is nothing like it used to be. People are staying away from high-rise Class A commercial buildings and migrating towards Class B units which are under five stories," Lynch continued. "We are always hustling to save a few bucks. Because people can get a lower per-square-foot net cost, we have to do something to make the buildings more attractive."
He added that he expects the building to rank much better on BOMA's comparative cost survey this year.
For more information on Sakto or this Press Coverage, please email info@sakto.com.
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