As concern for the environment has been dramatically raised over the recent decade, all fields have increased their efforts to reduce impact on environment. The field of construction has responded and started to develop the building performance strategies as well as regulations to reduce the impact on the environment. HVAC systems are obviously one of the key factors of building energy consumption. This study investigates the system performance and economic value of variable refrigerant flow (VRF) systems relative to conventional HVAC systems by comparing life-cycle cost of VRF systems to that of conventional HVAC systems. VRF systems consist mainly of one outdoor unit and several indoor units. The outdoor unit provides all indoor units with cooled or heated refrigerant; with these refrigerants, each indoor unit serves one zone, delivering either heating or cooling. Due to its special configuration, the VRF system can cool some zones and heat other zones simultaneously. This comparative analysis covers six building types—medium office, standalone retail, primary school, hotel, hospital, and apartment—in a eleven climate zones—1A Miami, 2A Houston, 2B Phoenix, 3A Atlanta, 3B Las Vegas, 3C San Francisco, 4A Baltimore, 4B Albuquerque, 4C Seattle, 5A Chicago, and 5B Boulder. Energy simulations conducted by EnergyPlus are done for each building type in each climate zone. Base cases for each simulation are the reference models that U.S. Department of Energy has developed, whereas the alternative case is the same building in the same location with a VRF system. The life-cycle cost analysis provides Net Savings, Savingto- Investment ratio, and payback years. The major findings are that the VRF system has an average of thirty-nine percent HVAC energy consumption savings. As for the results of the life-cycle cost analysis, the average of simple payback period is twelve years.

Master's thesis "VRF system" aims on the energy simulation of energy needs for HVAC system of one floor of the FSI NetMe Research Centre building and followed evaluation of the advantage of using VRF system with heat recovery function. The first part is a theoretical introduction, which describes the basics of the mechanical refrigeration, following the differences and ways of functioning of the VRF system with heat recovery function. Practical part of this work is aimed on the description of the way of data input into the simulation tool. Finally, the results of the simulation and economical comparation of the VRF system and the existing four-pipe cold and warm water distribution system are presented

This master thesis deals with VRF systems, which are used for extensive commercial and office buildings, or for buildings where there are multiple zones with different required parameters. The aim of the thesis is to explain the functions of the system and their evaluation and inclusion into energy classes according to the new legislation. The practical part deals with an application of the VRF system and its variants in the building of bank branch. The comparison of initials costs and resultant costs to operate the system. The experiment focuses on comparison of the measured values of VRF system and their comparison with data from the manufacturer.

The thesis deals with the issue will be nearly zero energy. The theoretical part is divided into several chapters. Describes the requirements of applicable legislation of the Czech Republic and the EU and the application of renewable energy in these buildings. The third and last part serves as a basis for part of the experiment. Calculation section applies theoretical knowledge into practice. The subject has become a new residential building in which they are designed to ensure the technical equipment required internal environment. The proposal concerns the heating, ventilation, cooling, domestic hot water and lighting. At the end are attached graphic of energy performance certificates (PENB) and evaluated the economic and ecological point of view. The experiment deals with the measurement of the internal microclimate administrative building type in Brno, with regard to the requirements of current legislation of the Czech Republic.