Being located in subtropical area, the weather in Taiwan is hot and humid which imposing huge cooling load on buildings. Conventionally, central air-conditioning plants were designed using refrigerant compressors to make chilled water, and then pumped through the zone pumps to meet the cooling load, providing air-conditioning by Fan Coil Unit (FCU) or Air-Handling Units (AHU) by ductwork. To meet the varying cooling demand, two important systems were developed for energy savings, namely, the Variable Water Volume (VWV) system, and the Variable Air Volume (VAV) system, which has been widely adapted in Taiwan area. The working principle is mainly devoted to adjusting the volume of the chilled water and/or air volume delivered through inverter-driven pimps and fans to achieve energy saving. On the other hand, recently in Japan, an important energy-saving air-conditioning system has been developed which directly varying the refrigerant flow rate to meet the varying cooling demand by inverter-driven compressors, named VRV system. Comparative to the conventional air-conditioning system, the heat exchange mechanism of the VRV system has been effectively enhanced by direct exchange of the refrigerant and the cool air, which is in effect a combination of the VWV and VAV system. It provided huge energy saving potential for the application on buildings with moderate cooling loads, such as 100 USRT or so. It is the goal of this research project, to evaluate the performance of the VRV system in Taiwan¡¦s hot and humid climate, by performing full-scale experimental investigation so that energy savings effect can be validated quantitatively. Since VRV system is fairly new in Taiwan, the validation of the system performance under local weather condition is of particular importance. It is anticipated that through the changing of the operation conditions, such as different outdoor conditions, various partial load conditions, and different scheduling of the VRV system, the power consumption of the VRV vs. conventional system can be compared precisely and quantitatively. These experimental data will, in turn, provides valuable reference to the establishment of the building energy consumption index in Taiwan, which outwits the direct adoption of the foreign data such as from Japan, in achieving a much reliable database.

Baigiamajame magistro darbe nagrinėjama problema – dideli energijos poreikiai vėsinimui biurų pastatuose, dėl vis didėjančių mikroklimato kokybės reikalavimų, didesnių šilumos pritekėjimų į patalpas ir šilumos išsiskyrimų dėl naudojamos įrangos. Problemos sprendimui darbe suprojektuotos keturios oro kondicionavimo sistemos su skirtingais šilumnešiais: oru, vandeniu ir freonu. Atsižvelgiant į šilumnešio tipą suprojektuotos ventiliatorinių konvektorių, aktyviųjų šalčio sijų, freoninė ir orinė vėsinimo sistemos. Oro kondicionavimo sistemos analizuojamos remiantis realaus tipinio administracinio pastato pavyzdžiu. Lyginamoms sistemoms buvo atlikti hidrauliniai ir aerodinaminiai skaičiavimai, įvertintos sistemų pradinės investicijos, apskaičiuotos energijos sąnaudos ir eksploatacijos išlaidos. Ekonominio skaičiavimo metu buvo įvertintas sistemų atsipirkimo laikas ir atlikta elektros kainų jautrumo analizė. Šio tyrimo rezultatai parodo, kokia sistema iš visų darbe nagrinėtųjų sistemų yra tinkamiausia biurų pastatams, pagal efektyvų elektros energijos naudojimą ir pradines investicijas. / The final master's work deals with the problem of high energy needs for cooling in office buildings, due to the growing of higher quality requirements for microclimate, higher heat gains in premises and equipment heat emissions used in. To solve the problem four different types of cooling systems with different coolants: air, water and refrigerant are designed at work. Depending on the type of coolant were designed fan coil units, active chilled beams, variable refrigerant volume system and air cooling systems. Air conditioning systems are analyzed on the basis of an example of the real typical office building. The hydraulic and aerodynamic calculations were made, initial investments, energy expenditures and operating costs were estimated for the compared systems. The pay-back time of the systems was assessed and the sensitivity analysis of electricity prices was carried out by economic calculations. The results of this investigation show, which system of all analysed systems at work is the most appropriate for office buildings, according to the efficient use of electricity and the initial investments.