Title: INNOVATIVE HYBRID GAS/ELECTRIC CHILLER COGENERATION

Abstract

Engine-driven chillers are quickly gaining popularity in the market place (increased from 7,000 tons in 1994 to greater than 50,000 tons in 1998) due to their high efficiency, electric peak shaving capability, and overall low operating cost. The product offers attractive economics (5 year pay back or less) in many applications, based on areas cooling requirements and electric pricing structure. When heat is recovered and utilized from the engine, the energy resource efficiency of a natural gas engine-driven chiller is higher than all competing products. As deregulation proceeds, real time pricing rate structures promise high peak demand electric rates, but low off-peak electric rates. An emerging trend with commercial building owners and managers who require air conditioning today is to reduce their operating costs by installing hybrid chiller systems that combine gas and electric units. Hybrid systems not only reduce peak electric demand charges, but also allow customers to level their energy load profiles and select the most economical energy source, gas or electricity, from hour to hour. Until recently, however, all hybrid systems incorporated one or more gas-powered chillers (engine driven and/or absorption) and one or more conventional electric units. Typically, the cooling capacity of hybrid chiller plants rangesmore » from the hundreds to thousands of refrigeration tons, with multiple chillers affording the user a choice of cooling systems. But this flexibility is less of an option for building operators who have limited room for equipment. To address this technology gap, a hybrid chiller was developed by Alturdyne that combines a gas engine, an electric motor and a refrigeration compressor within a single package. However, this product had not been designed to realize the full features and benefits possible by combining an engine, motor/generator and compressor. The purpose of this project is to develop a new hybrid chiller that can (1) reduce end-user energy costs, (2) lower building peak electric load, (3) increase energy efficiency, and (4) provide standby power. This new hybrid product is designed to allow the engine to generate electricity or drive the chiller's compressor, based on the market price and conditions of the available energy sources. Building owners can minimize cooling costs by operating with natural gas or electricity, depending on time of day energy rates. In the event of a backout, the building owner could either operate the product as a synchronous generator set, thus providing standby power, or continue to operate a chiller to provide air conditioning with support of a small generator set to cover the chiller's electric auxiliary requirements. The ability to utilize the same piece of equipment as a hybrid gas/electric chiller or a standby generator greatly enhances its economic attractiveness and would substantially expand the opportunities for high efficiency cooling products.« less

Authors:

Kollross, Todd; Connolly, Mike

Publication Date:

Wed Jun 30 00:00:00 EDT 2004

Research Org.:

Gas Research Institute (US)

Sponsoring Org.:

(US)

OSTI Identifier:

831192

DOE Contract Number:  

FC26-99FT40641

Resource Type:

Technical Report

Resource Relation:

Other Information: PBD: 30 Jun 2004

Country of Publication:

United States

Language:

English

Subject:

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; 03 NATURAL GAS; 33 ADVANCED PROPULSION SYSTEMS; AIR CONDITIONING; COGENERATION; COMMERCIAL BUILDINGS; COOLING SYSTEMS; ELECTRIC MOTORS; ENERGY ACCOUNTING; ENERGY EFFICIENCY; ENERGY SOURCES; HYBRID SYSTEMS; INTERNAL COMBUSTION ENGINES; NATURAL GAS; OPERATING COST