Case Studies
Washoe County Government
The Challenge
Washoe County is located in the northwest corner of the State of Nevada and covers the metropolitan cities of Reno and Sparks and surrounding areas. The main administration complex was facing replacement of its chillers and towers, which were initially oversized and running inefficiently for light load times. In spite of the chiller size, there were comfort complaints throughout Administration complex due to distribution piping problems. In addition, the large regional detention facility was suffering from very high energy bills, as were most of the County’s buildings.
Our Solution
The three buildings included in this retrofit were the Main Administration Complex, the Sheriff’s Office and Consolidated Detention Facility, and the downtown Reno Library. The project included the following Energy Conservation Measures (ECMs): Lighting Retrofit, Lighting Controls Installation, Plate and Frame Heat Exchanger Installation, VFD Installation, Chiller System Replacement, and Vending Miser Installation.
Lighting Retrofits: Replacement/Retrofit of lighting systems at all three facilities. Included conversion of T-12/Magnetic Ballasts to newer T-8/Electronic Ballast Technology, conversion of incandescent lamps to compact fluorescent lamps, installation of LED exit signs, all leading to a vast improvement in the lighting systems at these buildings while significantly reducing electrical demand and usage.
Lighting Controls Installation: Installation of wall and ceiling mounted occupancy sensors at the Administration Complex and the Sheriff’s Office, to shut lights out during periods of non-occupancy, resulted in additional reduction in electrical usage in addition to the savings achieved by the Lighting Retrofit.
Plate and Frame Heat Exchanger Installation: At the Detention Facility, a plate and frame heat exchanger was installed to utilize heat from the boiler system to pre-heat water needed for the dishwashers in the kitchen. By preheating the water, the existing electric booster heater is utilized much less, resulting in significant savings in the cost to heat that water.
VFD Installation: At the Administration Complex and the Detention Facility, Variable Frequency Drives (VFDs) were installed on several air handlers that had utilized inlet guide vanes or discharge dampers to vary the flow in Variable Air Volume (VAV) systems. The VFDs provide a much more efficient varying of the air which results in reduced electrical usage.
Chiller System Replacement: At the Administration Complex, two old in-efficient 250-ton Carrier chillers, that had become a maintenance burden to the County, were replaced with two new high-efficiency Trane rotary chillers, one a 150 ton machine and one a 350 ton machine. Additionally, the existing two cell cooling tower was replaced with two new BAC towers, sized to match the new chillers, and the existing chilled water and condenser water pumps were replaced with new pumps; also a plate and frame heat exchanger was installed to allow for free cooling during periods of lower cooling loads and low wet bulb temperatures. The sizing of the new chillers was done to allow a smaller chiller to operate during nights and weekends, and to allow for improved staging of chilling capacity by having a staggered size between the two chillers.
VendingMiser Installation: On 42 refrigerated vending machines located throughout all the County’s facilities the VendingMiser control device was installed, which shuts the machines off during periods of unoccupied time through the use of a wall mounted occupancy sensor, which significantly reduces the electrical usage by the machines.
Impact
This project saves the County over $179,032 annually in guaranteed energy savings
