摘要:

Evaporative cooling, extensively used in dry climates, can be justified in wetter areas by integration into HVAC systems; in this way the saving-energy technique will not always replace mechanical cooling, but has to be integrated with commonly employed equipment. In this paper Test Reference Year (TRY) data for Italy were processed to estimate using potential of multistage integrated evaporative HVAC systems. Specific humidity and wet-bulb temperature were computed to define five regions for external air, and then to evaluate hours per year and relative energy saving for each of these regions and Italian climatic areas. The systems subjected to comparison were a multi-stage evaporative—direct, indirect and mechanical—and a traditional mechanical one; both all air, single duct, single zone, constant volume systems with wet-bulb economizer. The method of analysis is based on a strongly simplified approach. It is not intended as a substitute for accurate modelling schemes to simulate building and system behaviour, but as a tool to estimate the energy saving potential related to the Italian climate. The following parameters have been assumed as constant throughout: sensible heat ratio of the conditioned space, adiabatic saturation and heat exchanger effectivenesses, indoor space and supply air temperatures and relative humidities. Outside air temperature and relative humidity are assumed to change hour by hour following the TRY profile. Energy savings are evaluated hourly, the mass flow rate of the supply air being kept constant. Seasonal energy savings for the majority of the climatic areas appears to be encouraging, ranging between 28% and 67% (space air temperature and relative humidity: 26°C −60%) or 36% and 74% (space air temperature and relative humidity: 26°C −70%). If it is assumed that the system operates always with 100% outside air (also for regions with outside wet-bulb air temperature greater than space wet-bulb air temperature) energy cooling requirements display different trends for different climatic areas.

ISSN:0143-0750    

DOI:10.1080/01430750.1997.9675252

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Theoretical and experimental investigations have been carried out upon the applications of the open-circuit voltage decay technique for the characterisation of a large spectrum of photovoltaic cells. The investigated samples are either locally fabricated or commercially available. The study clearly showed the effects of base resistivity value, manufacturing technique, as well as the nuclear radiation on the cells performance.

ISSN:0143-0750    

DOI:10.1080/01430750.1997.9675253

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The paper examines the extent to which user's intervention may compromise the thermal performance of small sunspaces in the context of a Solar Energy Demonstration Project at Easthall in Glasgow (55°52′N), which was monitored from September 1992 to May 1994. Results indicate a tendency to close down windows etc, late in autumn and open them up early in spring relative to heat demand. In other words a user-driven energy load due to ventilation is higher in autumn and spring than in the central winter period. However, effective rate of ventilation, taking account of the preheat effect of the glazed spaces, is found to be more steady over an entire heating season. Thus, inclusion of glazed buffers has been shown to lessen the thermal burden of window opening in autumn and spring; while saving in winter due to preheated air for ventilation tends to be slightly higher than predicted. Results also indicate that amount and frequency of opening/ventilation relates to specific social and occupancy characteristics; and that some users were able to trim their energy load by better use of the controls at their disposal in the second season. As a by-product, the monitoring has shown that energy models which take a steady rate of ventilation over a heating season are unrealistic.

ISSN:0143-0750    

DOI:10.1080/01430750.1997.9675254

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Much more attention is now being paid to local air pollution levels in Europe and America, led by the California Air Resources Board (CARB) who have pronounced that a given percentage of cars sold in that State must be zero emission by a certain date [1]. The obvious contender to fulfil such a requirement is the electric driven vehicle, but manufacturers are having problems producing a reliable battery of sufficient energy density.

ISSN:0143-0750    

DOI:10.1080/01430750.1997.9675255

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Although the Kingdom of Saudi Arabia is one of the main oil producing countries, yet the latest five year development plan calls for energy conservation [1]. Due to the expansion of the Saudi economy which is reflected by the challenging and ambitious development in various sectors such as housing, health, industry, agriculture, education etc, the consumption of electric energy experienced a sharp increase during the last twenty years. Electric energy consumption in the central region of Saudi Arabia increased from 4,236,000 MWh in 1981 to 12,996,000 MWh in 1988. Since 1983 the Ministry of Education started implementing various strategies to conserve energy consumption by school buildings. In the 1990s more attention is geared towards improving the U-value of the external envelope through the use of hollow blocks and thermal insulation. This study is an attempt to investigate the effectiveness of the use of thermal insulation and hollow blocks in reducing energy consumption. This is conducted by the analysis of actual electric energy consumption of some selected examples of school buildings in Riyadh. Also the study will investigate other energy conservation strategies which might yield additional energy savings. This shall be carried out through the analysis of Riyadh climate.

ISSN:0143-0750    

DOI:10.1080/01430750.1997.9675256

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:0143-0750    

DOI:10.1080/01430750.1997.9675257

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:0143-0750    

DOI:10.1080/01430750.1997.9675258

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:0143-0750    

DOI:10.1080/01430750.1997.9675259

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:0143-0750    

DOI:10.1080/01430750.1997.9675251

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor