GSR Chilled Water Pump Improvements - Savings of $60,000 per Year
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.
Turquoise Ridge Joint Venture - Peak Shaving - Savings of $336,686 per Year
March 2005, Winnemucca, Nevada
SES conducted a plant wide energy assessment at the Turquoise Ridge Joint Venture (TRJV) underground mine site near Golconda, NV. TRJV works two separate underground mines at this site, Turquoise Ridge and Getchell, with an expected production rate of 300,000 ounces of gold per year. More about TRJV can be found here. The two mines together, including administration buildings, shops, and assay labs, combine for a total energy demand of 7.3 MW, with the Turquoise Ridge mine being the single largest user of electricity with a demand of 4.9 MW. Currently, TRJV consumes a total of 51,238,196 kWhr of electricity at an average blended rate of $0.084101/kWhr, resulting in an annual electrical energy cost of over $4.3 million. The normal operation of the entire facility results in a cyclic demand profile, creating a relatively low overall load factor of 70-80%. Because of this low load factor, Sierra Pacific Power Company, the local utility provider, has placed TRJV in the GS-3 rate schedule. One of the recommendations resulting from the SES plant wide energy assessment was to use standby generators for shaving peak demands at the facility. Using these generators to flatten out the demand profile of the facility will result in a higher annual load factor, up to 90%. With this high load factor, TRJV can be placed into Sierra Pacific's GS-4 rate schedule, with an overall blended electricity rate of $0.0773/kWhr, an 8.1% reduction in energy costs. The implementation cost for the project was $238,960, resulting in an annual savings of $336,686 for a simple payback period of 8.5 months. Over the 5 year contract period required for GS-4 customers, it is estimated that TRJV will save over $1.4 million in electrical costs.
SES, working together with Sierra Pacific Power Company, was able to negotiate a better electricity rate schedule for TRJV. SES President Denis Donovan was very satisfied with the results. "SES was able to use our knowledge and expertise in Utility matters to negotiate an outstanding opportunity for our client." The negotiations continued for a period of 6 months but in the end Turquoise Ridge achieved a new rate schedule which should yield a minimum of $200,000 in annual cost savings. Donovan went on to say; "This result is a win-win, the utility company is encouraging improvements in load factors through a carrot approach and the client achieves the cost benefits of the new rate schedule immediately with additional savings as the load factor is improved."
Carson Valley Swim Center - Solar Domestic Water Heating Redesign
July 2005, Gardnerville, Nevada
Located in Minden Nevada, the Carson Valley Swim Center is a community swim center. The swim center consists of six pools of various sizes and temperatures. The swim center installed a solar thermal system over 18 years ago. Sustainable Energy Solutions was hired to perform an energy assessment to identify energy savings opportunities. The report identified several areas of opportunities, one of which was making some modifications to their current solar system. These modifications were modeled by SES's Project Engineer Mike Matheus using the powerful energy modeling software TRNSYS. Mike, one of only a few on the west coast capable of using TRNSYS, was able to run several "what if" scenarios using the TRNSYS model. "By using this software, I can see the impacts of control decisions, and different equipment selections on the annual energy usage, this allows me to maximize savings in a very realistic environment." Mike used this model to achieve an annual natural gas savings of 12%. "As the model evolved it became obvious that some of the control logic used was wrong and the older style heat exchangers were limiting the maximum energy transfer. I played with some brazed plate heat exchangers and tweaked the logic until I had optimized the system." The actual results achieved through the installation of 2 small brazed plate heat exchangers and redoing the controls matched the predicted results of the model to within 5%.
Carson Valley Swim Center - Dehumidification System Redesign
August 2005, Gardnerville, Nevada
In the Summer of 2005, SES was hired by the Carson Valley Swim Center (CVSC) in Gardnerville, Nevada to redesign their existing dehumidification system. The CVSC operates four indoor pools, including a slide pool with two large slides, year round and two outdoor pools during the summer months and serves over 500,000 visitors a year. Due to the large number of indoor pools and their warm temperatures, a high level of evaporation from the pools was creating a very uncomfortable and corrosive environment. The swim center utilized 3 mechanical dehumidification units which utilize a refrigeration cycle to condense water out of the air. These units, when functioning would consume a large amount of energy in the refrigeration compressors. Unfortunately the refrigeration system on these units was prone to mechanical failure. The effect was expensive operating and maintenance costs to achieve a comfortable environment. SES was called in to provide a design which would achieve the desired indoor environment, cause minimal disruption to the facility, and be energy efficient. Project Engineer Mike Matheus recognized the solution immediately. "Northern Nevada air!" Mike wanted to bring in a certain percentage of outside air and use this to absorb the moisture generated by the evaporation from the pools. By installing 2 exhaust fans with energy recovery coils, Mike was able to exhaust the moist, chlorine enriched air to the outside, transfer the energy of that warm moist air to the dry outside air to achieve an energy efficient dehumidification system. The original dehumidification systems were left in place and Mike estimates the compressors run time will be minimal. "We get an occasional thunder storm in the middle of a hot summer day, this will drive up the outside air humidity and prevent the desired moisture absorption. This and the occasional scorcher will cause the refrigeration system to operate."
SES has found a sustainable, cost effective solution for this client, we can do the same for you.
The Residences at Riverwalk Towers - Chilled Water Engineering Design
October 2005, Reno, Nevada
In June 2005, SES was commissioned to finalize the engineering design at a new, upscale condominium project in Reno, NV. The Residences at Riverwalk Towers will be the first condominium conversion project to be completed in downtown Reno. When SES took on the project, the building had already passed the demolition stage and the new condos were well on their way to being completed. SES was commissioned to design a central chilled water plant for the building, even though the distribution system, including piping, fan coils, and control valves, had already been installed.
Erik Boyer, a Project Engineer for Sustainable Energy Solutions took on a larger than anticipated job. "The pipes were in place, the fan coils and control valves already in place, they just hadn’t gotten to the central plant." The building was formerly the Comstock Hotel and Casino, a 16 story tower with fantastic views of the surrounding Reno area. The original engineer had designed a chilled water distribution system which was not optimal for the building layout. Both the main supply and return lines were undersized for the anticipated cooling load, severely limiting the amount of chilled water that could be supplied to the fan coil units which had already been installed. Faced with pressure issues induced by the poor design of the chilled water distribution and the limited flow rates allowed in the undersized piping, a variable primary chilled water loop was selected as the design. This type of design relies on tight, fast controls for flawless operation and equipment protection. "Knowing that I was using Quality Controls Systems as the controls contractor gave me a lot of comfort pursuing this project. Their system, ALC, is fantastic", Erik said. Using the ALC system Erik was able to vary the speed of the main chilled water supply pump and control the staging of the chiller compressors to meet the cooling demands of the building while preventing any damage to the chiller from low flow conditions. By anticipating the daily loads, the system will be able to cool the loop down in stages dropping to a low loop temperature of 42ºF. With the ability to drop the loop temperature down to 42ºF, Erik was able to decrease the required chilled water flowrate to the building, minimizing the impact of the undersized distribution piping.
With this project, SES was faced with a difficult task; complete a system that has been half designed and half installed. However, the design engineering team at SES was, once again, able to think outside the box to design an energy efficient chilled water system that exceeds all of the system performance requirements.
