McQuay chillers more than double in energy costs

Johnson County's office building, Sunset Drive, in Olathe, Kansas, was designed from the ground up to produce the least damage to the environment and the best impact on the people who use the building. In 2006, the Green Building Rating System, Leadership Energy and Environmental Design (LEED) awarded the building gold certification in New Construction (NC) version 2.1; a recognition that attested to the achievement of both goals and that has made it a reference for other buildings.

Sunset Drive was designed to save about 40% in energy costs compared to the benchmark defined in ASHRAE 90.1, the U.S.-accepted energy performance benchmark.

To test the energy performance of the construction, for six months, between May and October 2006, they performed a comparative study on the building with a pair of its also owned by the county, but 15 years older, and which is also built under the ASHRAE 90.1 standard.

During the study time, the Sunset Drive saved 57% in energy costs. Too much, if we remember that both buildings are manufactured taking into account the reference point defined in ASHRAE 90.1.

A factor that was relevant to achieve such energy savings was the design of the air conditioning system, which also contributed eight points in the energy and atmosphere category, for the LEED award.

McQuay frictionless chillers

- Publicidad -

In the building, the heart of the air conditioning system is a pair of water chillers with frictionless centrifugal compressor from MacQuay, these frictionless systems compared to other chillers, consume a minimum of electricity, since with partial load, they consume 0.20 kW / ton of cooling capacity, the most efficient performance in all chillers on the market within their tonnage. At full load, the same chillers are about 10% more efficient than regular screw compressor coolers.

The key to cooler efficiency is the digitally controlled magnetic bearing system in the cooler, replacing conventional lubricated bearings. When in use, the only moving part of the cooler, the control shaft, is suspended in the air by a system of permanent magnets and electromagnets. The localization signals received by the electromagnets hold the shaft in the precise position with a tolerance margin of 0.00005 inches (0.0001 mm). The axis position is tested and adjusted 10,000 times per second.

Benefits with chillers

• McQuay frictionless cooler uses HFC-134ª refrigerant gas

• The vibration and noise associated with other types of chillers is virtually eliminated.

• Since frictionless coolers need less power, they can be built with permanent magnet motors that do not require extra current at start-up.

• The impeller is only a few centimeters in diameter and operates at speeds of up to 30,000 rpm.

• No oil is required to lubricate the bearings, so there are no oil pumps, filters, chillers or heaters, and no need to dispose of used oil. Only a small amount of oil is used to lubricate other system components, such as seals and valves.