Improving Economics for District Energy Systems

Project objective

A large Canadian utility involved in developing district energy systems that include cogeneration had a surplus of heat energy in non-space heating months. The economics of these systems had significant potential for improvement if waste heat could be utilized for the production of chilled water. Absorption chillers offered a method to convert waste heat into usable chilled water.

Comprehensive scope of work

The scope of work by Kinectrics involved identification of heat-driven cooling technologies, and equipment applicable to the client’s district cooling systems operated in conjunction with co-generation of electricity and heat. A second task looked at the economics of heat-driven chillers versus electric chillers.

State-of-the-art steam turbine and absorption cooling cycles that could be used with cogeneration systems were reviewed, including double and triple effect systems in development. The work covered steam, gas turbine and combined cycle co-generation applications. Kinectrics investigated different options in using heat-driven cooling in conjunction with central cogeneration in the district energy systems.

Detailed assessment

Questions and issues addressed by Kinectrics included:

• Operation of absorption chillers from gas turbine exhaust, including microturbines
• Use of cooling coils at gas turbine inlet for efficiency improvements
• Can absorption chillers using water-lithium bromide generate water chilled sufficiently for district cooling requirements? If not, what other technology can be used?
• How do chilled and hot water district heating systems with central chillers compare to steam district heating systems with steam-driven absorption chillers at customer sites?
• Can absorption chillers be operated from a high-temperature water distribution system?
• How do steam turbine-driven chillers compare to absorption chillers?
• What is the reliability determination for absorption chillers?

Practical, documented solution 

Kinectrics provided a comprehensive, documented review of heat-driven cooling technologies for the project and developed a detailed spreadsheet that allows the client to readily analyze the economics of various types of chillers in a cooling plant.

Delivering value

The client gained a powerful tool to enable effective selection of the appropriate cooling equipment for installation in its district energy systems.

For more information, info@kinectrics.com