2014 Big Ten & Friends Mechanical and Energy Conference
Presentation Abstract Example
Abstract Title
Application of Water/Water Heat Pumps Using Chilled Water Return as the Heat Source
Author #1
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Author #2
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Institution/Company
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Learning Objectives:
1. Overview of the design concept using water-to-water heat pumps using the campus chilled water return water as the
heat source for building heat in the winter and building reheat in the summer.
2. Energy balance of the system
3. Implementation and operating costs
4. System controls
Content (Please limit to 300 words)
Several recent projects at the University of Iowa are implementing a concept to utilize the University’s campus chilled
water loop as a heat source for both heating the building in winter and providing required reheat in summer. Most of
the university’s buildings have a substantial winter time cooling load due to large internal areas with no exterior
exposure and in some cases, process cooling loads. Essentially, these buildings are generating waste heat in the
winter since the part of the building where the heat is generated (the core) is separated from the part of the building
where the heat is needed (the perimeter). The campus chilled water network provides a unique opportunity to harvest
waste heat from existing buildings to provide useful heat for new ones. Through the use of a heat recovery chiller, heat
will be extracted from the campus chilled water loop to provide heat for a new building while simultaneously providing
useful chilled water to other existing campus buildings.
Implementation of this concept results in a significant reduction in energy consumed since the amount of heat
harvested is over 4 times the energy used to extract it. In addition, during times of the year when the operation of the
heat pump corresponds to use of the central plant chillers (spring, summer and fall), the chilled water produced as a
byproduct of generating heat reduces the load on the central chillers. In this way, the total useful heating and cooling
energy produced by this system can be as much as 7 times the energy consumed. Although the chillers, controls and
heating distribution equipment used in this concept are readily available and fairly conventional, they are applied in a
unique configuration in order to realize this high performance.