The Grand Sierra Resort is a large casino-resort property located in Reno, NV.  With over 80,000 square feet of public space, the energy usage in the  building is significant.  The chilled water used throughout the building is supplied from the central plant’s two 1,500 ton Carrier Chillers.  During peak summer months the original chilled water system was not able to meet the flow requirements forcing the plant operators to bring a second chilled water pump and chiller online, increasing the chilled water plant’s kW demand to more than 1,025 kW.  SES worked with the GSR facility engineers to identify opportunities to reduce the energy usage in the chilled water system.  Through re-installing automatic flow balancing valves and the installation of a properly sized chilled water pump with a variable speed drive, the GSR was able to reduce the run time on the second chiller by more than 350 hours in the first month of operation, saving more than 180,000 kWhr and $20,000 in the first month.  Once all the automatic flow balancing valves are re-installed in the guest rooms, the VSD on the new chilled water pump will allow the GSR to realize energy and  cost savings throughout the year with annual estimated cost savings of over $60,000/yr. 

EP Mineral Clark Plant Cogeneration System - Savings of Over $860,000 per Year

EP Minerals is an industrial minerals company that produces diatomaceous earth products.  EP’s Clark Plant operates three separate production circuits, 1 rotary kiln and 2 flash dry, where the product is classified, dried, and in the case of the kiln, calcined.  The rotary kiln uses a combination of natural gas and used oil to dry and calcine the product at temperatures of 1,200°F and produces 6.5 TPH of finished product.  The Clark plant has an average electric demand of 1,300 kW, an annual electrical energy usage of over 8,700,000 kWhr/yr, and uses over 72,000 Dth of natural gas and 750,000 gallons of used oil annually.  With increasing energy costs and the availability of used oil becoming unreliable, EP Minerals was looking for ways to significantly reduce the operating costs at their Clark Plant. 

With the high electrical and thermal loads required at Clark, cogeneration was an obvious choice for reducing energy costs.  SES worked with EP Minerals to first conduct a full scale feasibility study and economic analysis to determine if cogeneration was viable at Clark. Through the feasibility study all aspects of the cogeneration system were analyzed including: detailed mass and energy balances, identification of technical hurdles that would need to be overcome in the system design, negotiations with the Utility Company, identification and procurement of fuel supply as well as a full scale economic analysis based on the past two year’s 15-minute electrical demand data for the facility as well as forecasted fuel and energy costs. With the completion of the feasibility study it was determined that the Clark facility was a great candidate for cogeneration and SES was hired to complete the full system design.

The cogeneration system designed by SES consists of a refurbished Solar Saturn 20 gas turbine rated for 1.2 MW of electrical power and 9.65 MMBTU/hr of waste heat.  The waste heat from the gas turbine is used to simultaneously dry and pneumatically convey the raw product prior to entering the kiln.  The cogeneration system came online in March 2009 and preliminary data show just how effective the utilization of the waste heat is.

Before the installation of the cogeneration system, the average kW demand at the facility was over 1,300 kW and the kiln would use approximately 400-450 scfm of natural gas to produce 6.5 TPH of finished product.  After the cogeneration system was installed, the facility kW demand dropped to 500 kW and the fuel usage in the kiln decreased to 160 scfm, a 62% reduction in kiln fuel usage.  During this time, the turbine was producing 800 kW of electrical power and using 220 scfm of natural gas.  Thus, the total natural gas for the facility was 380 scfm, still less than what the kiln used prior to the installation of the cogeneration system.  The initial results from the cogeneration system not only indicate a significant cost savings for the Clark Plant, but also a significant improvement in the overall thermal efficiency of the kiln circuit.  Based on the preliminary results, the cost savings associated with the cogeneration system at the Clark Plant will top $860,000/yr.