Articles Copyright (c) 2013 Southern Illinois University Carbondale All rights reserved. http://opensiuc.lib.siu.edu/meep_articles Recent documents in Articles en-us Sat, 26 Jan 2013 23:01:21 PST 3600 Review and Analysis of an Energy Efficiency Incentive Program for Commercial Buildings http://opensiuc.lib.siu.edu/meep_articles/6 http://opensiuc.lib.siu.edu/meep_articles/6 Fri, 02 Apr 2010 11:49:12 PDT A program with 13 participants provided reimbursement for improvements to decrease energy use largely in commercial and not-for-profit buildings but also in two government buildings. Electricity and natural gas savings were determined by modeling the energy use by accounting for changes in weather for the 12 months previous to the improvements, and then predicting energy use for the 12 months immediately after the improvements using the same model.

The threshold for verifiable energy savings resulting from building improvements was a maximum uncertainty of 50% at the 68% confidence level. Improvements involving original furnace or air conditioner replacement resulted in significant and verifiable reductions in energy use. Energy savings due to lighting improvements were verified for only one of seven buildings in which lighting was upgraded. Verifiable results were obtained in buildings with constant usage patterns, hours of operation, and equipment. Significant changes not related to weather, and improvements resulting in less than 10% savings of the total energy measured at the meter led to non-verifiable results.

Other benefits of the program not related to energy cost savings included increasing illumination while maintaining the same electricity use, and improving comfort and noise reduction with additional insulation. The program was very successful in leveraging significant private investment for building improvements. In addition, the program inspired business owners to make further improvements voluntarily after the program ended and also increased interest in similar future programs.

]]> James A. Mathias et al. Experimental Determination of the Insulating Ability of Corn By-Products http://opensiuc.lib.siu.edu/meep_articles/5 http://opensiuc.lib.siu.edu/meep_articles/5 Fri, 02 Apr 2010 11:37:01 PDT This article proposes and experimentally tests a way to better utilize renewable agricultural products that, if successful, will increase revenue for agricultural producers, decrease the amount and cost of disposal of non-renewable products, and decrease the amount of non-renewable products that need to be produced. In this article the insulating ability of ground corn cobs is compared, by experimental tests, to typical fiberglass, cellulose, and Rock Wool insulation. The study found that the insulating ability of ground corn cobs is not as great when compared to typical insulations, but using a greater thickness of insulation made from ground corn cobs or combining this insulation with typical insulations may be beneficial. In conclusion it is valuable to know how the insulating ability of ground corn cobs compares with typical insulations to determine if further research in this area is beneficial and to stimulate other possible ways to use renewable agricultural products.

]]> Anna Dowling et al. Experimental Testing and modeling of a Dual-Fired LiBr-H2O Absorption Chiller http://opensiuc.lib.siu.edu/meep_articles/4 http://opensiuc.lib.siu.edu/meep_articles/4 Fri, 02 Apr 2010 09:54:03 PDT An LiBr-H2O chiller was modified to utilize heat sources from natural gas combustion and/or from hot fluid. This was achieved by replacing the original gas-fired generator with a dual-fired generator. Steam was used as the hot fluid. The generator of the chiller can be powered by each source separately or both sources simultaneously. Experimental investigation was performed to obtain capacity and coefficient of performance (COP) of the original chiller and the modified chiller. During the experiments, the modified chiller was powered solely by steam, natural gas, or both. There was a significant increase in COP and capacity when steam was used as a heat source. The tests using natural gas resulted in performance similar to the original chiller. The experimental conditions were closely modeled by a numerical program.

]]> Tom A. Gee et al. Energy Efficient, Cost Effective, Passive Solar House http://opensiuc.lib.siu.edu/meep_articles/3 http://opensiuc.lib.siu.edu/meep_articles/3 Thu, 18 Mar 2010 07:07:57 PDT A house was constructed in Carbondale, IL, in the mixed humid climate region, using the best current construction methods with commonly available materials. Good passive solar characteristics were obtained by properly orientating the house to have many south-facing windows with proper overhangs which provided 23% of the energy needed for heating. The house also included 15 cm (6 in) thick insulated walls, insulated concrete forms for foundation walls, insulated rim joist, a ground-source heat pump, Energy-Star windows, clothes washer, refrigerator, and compact fluorescent bulbs (CFLs).

Electrical usage data was metered separately for heating, air conditioning, hot water, lights and appliances. The energy used by the actual house was compared to the same sized house built to the International Energy Code Council 2004 Residential Energy Code. The actual house used 7809 kWh (50%) less than the code house for an annual cost savings of $826. The annual on-site electricity used by the house was 19.8 kWh/m2. Cost of the energy-efficient improvements in the actual house was $7,990. The house was very cost-effective by using commercially available materials and employing an on-site general contractor knowledgeable in maintaining the high energy-efficiency standards designed into the house, coordinating the work, and allowing the homeowners to perform manual tasks. This method resulted in a price of $1,062/m2 ($99/ft2) of finished floor area, noticeably less than a comparable house in the region.

]]> James A. Mathias et al. Investigation of Optimal Heating and Cooling Systems in Residential Buildings http://opensiuc.lib.siu.edu/meep_articles/2 http://opensiuc.lib.siu.edu/meep_articles/2 Thu, 18 Mar 2010 06:48:13 PDT This article compares four heating and cooling systems. The systems are: a high efficiency furnace and electric air conditioner; a ground source heat pump; an absorption air conditioner and direct heating; and a thermally driven heat pump; the last two systems use solar thermal energy and backup non-renewable energy. A comprehensive program was developed that predicted the entire life cycle cost, energy usage, exergetic efficiency, and exergy destruction, of all four systems operating in the same home figuratively placed in the cities of Louisville, KY; Houston, TX; Minneapolis, MN; Sacramento, CA; and Phoenix, AZ. The results showed that the vertical ground source heat pump always paid back in the shortest time, between 4-15 years in all five cities compared to the furnace and air conditioner system. The economic pay back period was the shortest between 4- 7 years in the cities of Louisville. Minneapolis, and Phoenix, which have larger heating and/or cooling requirements. The thermally driven heat pump, which largely used renewable energy, had equal or greater exergetic efficiency than the ground source heat pump in each city, while the furnace and air conditioner always had the lowest exergetic efficiency.

]]> Angela L. Bolling et al. Improving Efficiency in a Campus Chilled Water System Using Exergy Analysis http://opensiuc.lib.siu.edu/meep_articles/1 http://opensiuc.lib.siu.edu/meep_articles/1 Thu, 18 Mar 2010 06:31:15 PDT This paper evaluates the central chilled water system of the Southern Illinois University Carbondale (SIUC) campus using exergy-based cost accounting to quantify the magnitudes and cost impacts of internal losses with the goals of maximizing chiller capacity utilization and minimizing the unit cost of delivered chilled water. Two independent systems, each comprised of a primary-secondary-tertiary distribution network and cooled by a 12,300 kW (3,500 RT) steam-turbine driven centrifugal chiller, were modeled as control volume networks using steady-state rate balances for energy, exergy, and cost. An extensive set of measurements, collected over the 2006 cooling season, was used as the input data for the models. Results show that while the steam turbines are the largest source of exergy destruction, mixing in the distribution loops is the dominant source of exergy unit cost at low cooling loads, and refrigeration cycle losses dominate costs at high loads. Recommendations include: (1) Convert the chilled water distribution to an all-variable-speed, direct-coupled configuration; (2) During low cooling loads use only one chiller; (3) During high cooling loads, increase the flow rate of water through the evaporators; (4) Favor speed control over inlet guide vanes for capacity modulation; (5) Better insulate steam piping; and (6) Consider replacing the steam turbines with variable speed motors.

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