【導(dǎo)讀】達(dá)1至萬千瓦時(shí)。幾項(xiàng)新的措施，如分布式、二次循環(huán)、及先進(jìn)的獨(dú)立式制冷。系統(tǒng)的使用，可以顯著地減少制冷劑使用量，同時(shí)相應(yīng)降低制冷劑的泄漏損失。允許在非常低的水頭壓力下運(yùn)行。通過適當(dāng)?shù)脑O(shè)計(jì)和實(shí)施，這些先進(jìn)的系統(tǒng)，每年。可以通過水源熱泵機(jī)組，通過設(shè)在該散熱循環(huán)熱。這種集成方法表明，可以減少％的制冷和空調(diào)系統(tǒng)綜合經(jīng)營成。在商業(yè)部門中，超市是最大的能源用戶。一個(gè)銷售面積約40000英尺的典型的。耗高達(dá)3至5萬千瓦時(shí)/年的情況。超市的能源消耗總量中，壓縮機(jī)和冷凝器占30％至35％，其余是消耗在：展示。藏裝置中直接采用膨脹線圈。為了降低噪聲和控制散熱，壓縮機(jī)和冷凝器保存在遠(yuǎn)。置正在考慮要求大大減少制冷劑。關(guān)于這項(xiàng)調(diào)查的工作仍在繼續(xù)，因此，冷凝溫度最低為60華氏度，僅限于本評估。尚未得到最優(yōu)化，壓縮機(jī)制造商并沒有為這部分提供分析。上升導(dǎo)致溫度升高帶來了較高的冷凝溫度。

　　

【正文】 eed the required refrigeration load. Otherwise, excessive pressor cycling will occur, making it difficult to control case temperature. The use of pressor unloading allows the condensing temperature to vary with ambient temperature, since the unloading reduces pressor capacity and helps to match the capacity to the refrigeration load. Modeling of the scroll pressor included unloading for capacity control in order to maintain the suction pressure setpoint. The unloading is modeled as a continuous process, 19 and the pressor power is modeled using the standard relationship for power change with pressor unloading. Figure 6 shows the relation between capacity control and pressor power required. Figure 6 Relation between capacity and power used for modeling unloading scroll pressors. For analysis the minimum condensing temperature was set at 40176。F and 60176。F for low and mediumtemperature refrigeration, respectively. This may or may not be practical, since two glycol loops are needed in order to have two different minimum condensing temperature values. The close coupling of the pressor to the case evaporator seen in selfcontained systems reduces the pressure drop at the pressor suction and also minimizes the heat gain to the suction gas. Both of these effects will result in more efficient operation and were included in the analysis. CONCLUSIONS The results of this analysis showed that the greatest refrigeration energy savings for a supermarket application were achieved by a distributed refrigeration system with aircooled condensing, a lowcharge multiplex system with evaporative condensing, and a 20 secondary loop also with evaporative condensing. An advanced selfcontained system approach showed higher energy consumption than the baseline multiplex system. The power penalty associated with pressor unloading along with energy required for glycol loop pumping contributed to this increase. The supermarket refrigeration systems showing lowest TEWI were the distributed pressor and secondary loop systems employing the glycol loop and evaporative heat rejection. The lowest direct warming impact was demonstrated by the advanced selfcontained system, but these reductions were offset by the higher indirect impact due to increased energy use. The use of watersource heat pumps with refrigeration systems employing glycol loops for heat rejection was found to produce operating cost savings due to bined savings for refrigeration and HVAC. Distributed and secondary loop systems in this configuration showed significantly higher savings than those obtained by multiplex refrigeration with heat reclaim. Further energy savings could be realized by refrigeration systems employing scroll pressors if midscroll injection for subcooling were employed. Unfortunately, the savings that can be obtained could not be quantified here due to a lack of available design or operating data for pressors of this type. Because of the energy and cost saving potential that lowcharge refrigeration systems have, the . DOE has extended the efforts in this investigation to include field testing of a distributed refrigeration system employing a glycol loop and WSHP for HVAC. This particular system is now installed in a supermarket operating in the suburbs of Worcester, Mass. This store was instrumented to gather energy and operating data for the refrigeration and heat pump systems. At the same time, a second store in close proximity to the distributed store was also instrumented. The second store employs a stateoftheart multiplex refrigeration system and conventional, rooftop HVAC. Both sites are now being monitored. In addition, a second field test has been started in the Los Angeles, Calif., area for the California Energy Commission (CEC)1 that will involve the design and field testing of a 21 secondary loop refrigeration system. Test results obtained from this field demonstration will plement those obtained in the DOE low refrigerant charge system field testing. ACKNOWLEDGMENTS The authors would like to acknowledge the support and direction provided by Dr. Esher Kweller of the . DOE. This work was sponsored by the . Department of Energy, Office of Building Technology, State and Community Programs under contract DEAC0500OR22725 with UTBattelle, LLC. REFERENCES [1]Sand, ., . Fisher, and . Baxter. 1997. Energy and global warming impacts of HFC refrigerants and emerging technologies. Oak Ridge National Laboratory, Oak Ridge, Tenn. Sponsored by the . Department of Energy and AFEAS. [2]Walker, . 2020. Lowcharge refrigeration for supermarkets . IEA Heat Pump Center Newsletter, Sittard , the Netherlands, Volume 18, No. 1. [3]Walker, . 1997. Development of an evaporative condenser for northern climates. Prepared for Niagara Blower Company and New York State Energy Research and Development Authority (NYSERDA), Foster Miller, Inc. Waltham, Mass. [4]Walker, David . Development and demonstration of an advanced supermarket refrigeration/HVAC system. Final Analysis Report, ORNL Subcontract Number 62XSX363C, FosterMiller, Inc., Waltham, MA 02451.