Daikin UWL040B5 - Page 25

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The switchover between water-cooled chilled water and water-source hot water modes can be achieved easily by the
opening and closing of valves in the water system to meet the annual demand for cooling or heating. The cold and
heat source can be waste heat, geothermal source, water source and others. The operation is more efcient and more
ecofriendly.
USING SIDE
WATER RETURN
V1
V2
COOLING/HEATING MODE
V1
V1
V1
V2
V2
V2
USING SIDE
WATER SUPPLY
HEAT SOURCE SIDE
WATER SUPPLY
HEAT SOURCE SIDE
WATER RETURN
UWL
EVAPORATOR
CONDENSER
Mode V1 V2
Cooling Open Close
Heating Close Open
Hydraulic calculation and pipe system
Pipe design for the air-conditioning system
■ The pipes of an air conditioning system must have sufcient transportation capacities. For example, the water system
must ensure that the water owing through the air conditioning unit or fan coil reaches the rated ow rate to ensure
that the unit works properly.
■ Deploy pipes properly. Use pipes with reverse return if possible. Although the initial investment is increased a little, the
water ow in the system is more stable. If pipes have no reverse return design, pressure between branch pipes must
be balanced in the design process.
■ When determining the diameters of pipes, ensure that the transportation capacity is sufcient, the resistance and
noise is minimal, and that the unit works economically. A larger pipe diameter requires more investment, but the ow
resistance is smaller, the circulation pump consumes less energy, and the operation cost is smaller. Therefore, a
balance needs to be achieved between the operation cost and investment by designing the pipe diameter properly.
Avoid a large water ow with small temperature variation to ensure that the pipe system is economical.
■ In the design process, calculate water resistance accurately to ensure that water pressures between circuits are well
balanced and that the air conditioning system works with the best water and thermal conditions.
■ The pipe system of an air conditioning system must meet the adjustment requirements for partial workload.
■ The pipe system of an air conditioning system should use energy saving technologies whenever possible.
■ Pipes and accessories of the pipe system must meet the related requirements.
■ The design of the pipe system must facilitate maintenance, operation, and adjustment.