TEBIN engineeres apply advanced technologies to engineering decision making. One example of such solutions is the use of VRF systems for air conditioning and heating.
Variable refrigerant flow (VRF) is an air-condition system configuration where there is one outdoor condensing unit and multiple indoor units. The term variable refrigerant flow refers to the ability of the system to control the amount of refrigerant flowing to the multiple evaporators (indoor units), enabling the use of many evaporators of differing capacities and configurations connected to a single condensing unit. The arrangement provides an individualized comfort control, and simultaneous heating and cooling in different zones, and heat recovery from one zone to another.
We have positive experience in the application of VRF systems for air conditioning and heating of office and commercial premises with total built-up area over 40,000 sq.m. The system is both a source of cold and heat supply in the range of temperatures from -25C to +48C. This system in combination with heat recovery units allows to get free hot water in summer and effective heating in winter. For air handling units it is proposed to use external units as air cooling/heating units. VRF systems allow to make zone commissioning of each floor (room). Due to the fact that the outdoor unit can work with a minimum load of 10%, tenants can fill offices gradually, independently of each other.
VRF technology yields exceptional part-load efficiency. Since most HVAC systems spend most of their operating hours between 30-70% of their maximum capacity, where the coefficient of performance (COP) of the VRF is very high, the seasonal energy efficiency of these systems is excellent.
With a higher efficiency and increased controllability, the VRF system can help achieve a sustainable design. VRF is a technology that alternates the refrigerant volume in a system to match a building’s precise requirements. Only a minimum amount of energy is required for a system to maintain set temperatures, and ensure that it automatically shuts off when no occupants are detected in a room. This unique mechanism achieves more sustainability in the long run, as end users save on energy costs while reducing their system’s carbon emissions.
One attractive feature of the VRF system is its higher efficiency compared to conventional units. Cooling power in a VRF system is regulated by means of adjusting the rotation speed of the compressor which can generate an energy saving around 30%.
Other sustainability factors include:
- Use of non-ozone depleting environment-friendly refrigerants such as R-410a.
- Opting for heat pump instead of electrical resistance heating in areas demanding both cooling and heating. Heat pumps offer higher energy efficiency.
Thus, the application of such systems solves several tasks at once:
• hot water supply;
• heating and cooling supply of ventilation systems;
• helps to achieve a sustainable design (LEED, BREEAM certification).