Chilled water loop
In the air side loop, a cooling coil is used to cool and dehumidify the supply air. As mentioned, the cold fluid flowing through the tubes of the coil could also be either water or liquid refrigerant. Systems that use water flowing through the cooling coil also contain a relaxing water loop.
Evaporator
Heat energy flows from a better temperature substance to a lower temperature substance. Therefore, so as for warmth to be transferred from the air, the fluid flowing through the tubes of the cooling coil must be colder than the air passing over the tubes and fins. For example chilled water at 42°F(5.6°C) flows through the coil, absorbing heat from the air. The water leaves the coil at a warmer temperature @ 57°F(13.9°C).
It has also been mentioned that the water flowing through the cooling coil must be colder than the air passing through it. A heat exchanger is used to cool the water that returns from the coil- at 57°C(13.9°C) back to desired supply water temperature of 42°F(5.6°C). This heat exchanger, called an evaporator, is one component of refrigeration (cooling) equipment.
It has also been mentioned that the water flowing through the cooling coil must be colder than the air passing through it. A heat exchanger is used to cool the water that returns from the coil- at 57°C(13.9°C) back to desired supply water temperature of 42°F(5.6°C). This heat exchanger, called an evaporator, is one component of refrigeration (cooling) equipment.
Shell and tube evaporator
A shell and tube evaporator that has cold liquid refrigerant flowing through the tubes. Warm water enters at one end of the shell and fills the space surrounding the tubes. Heat is transferred from the water to the refrigerant inside the tubes, and chilled water leaves from the opposite end of the shell.
Pump and control valve
The third component of the chilled water loop may be a pump that moves water round the loop. This pump must have enough power to maneuver the water through the piping, the evaporator, the tubes of the coil, and the other accessories installed within the chilled water loop.
Similar to the airside loop, the chilled water loop responds to changing cooling loads by varying either the temperature or the number of water delivered to the cooling coil. The most common method, however, is to vary the number of water flowing through the cooling coil by employing a control valve. As the cooling load decreases, the modulating control valve reduces the speed of chilled water flow through the coil, decreasing its cooling capacity.
Similar to the airside loop, the chilled water loop responds to changing cooling loads by varying either the temperature or the number of water delivered to the cooling coil. The most common method, however, is to vary the number of water flowing through the cooling coil by employing a control valve. As the cooling load decreases, the modulating control valve reduces the speed of chilled water flow through the coil, decreasing its cooling capacity.
Two way versus three way valves
At part load conditions, a two way control valve reduces the speed of chilled water flow through the coil. A three way control valve also reduces the speed of flow through the coil, but it bypasses the surplus water to combine downstream with the water that flows through the coil.
With a three way valve, the quantity of water flowing through the system (water flowing through the coil plus water bypassing the coil) is constant at all loads. With a two way valve, the water flowing through the system varies, which allows the pump to scale back its capacity and save energy at part load.
Notice that the control valve is found at the outlet, or downstream, of the cooling coil. This location ensures that the tubes inside the coil are always filled with water. A valve located at the inlet, or upstream, of the coil may modulate to the purpose where the water just “trickles” through the tubes, not filling the whole tube diameter. The result's unpredictable heat transfer and fewer stable control.
With a three way valve, the quantity of water flowing through the system (water flowing through the coil plus water bypassing the coil) is constant at all loads. With a two way valve, the water flowing through the system varies, which allows the pump to scale back its capacity and save energy at part load.
Notice that the control valve is found at the outlet, or downstream, of the cooling coil. This location ensures that the tubes inside the coil are always filled with water. A valve located at the inlet, or upstream, of the coil may modulate to the purpose where the water just “trickles” through the tubes, not filling the whole tube diameter. The result's unpredictable heat transfer and fewer stable control.
Small chilled water system
A packaged water chiller produces chilled water by transferring heat from the water to the refrigerant inside the evaporator. This chilled water flows through the cooling coils, where it's wont to cool and dehumidify the availability air. A pump is employed to circulate water through the evaporator, the piping, the cooling coils, and therefore the control valves. Finally, each cooling coil is provided with a 3 way control valve that varies the speed of chilled water flow through the coil in response to changing cooling loads.
Hope you got the information about the chilled water. Please comment for any queries
This is dummy text. It is not meant to be read. Accordingly, it is difficult to figure out when to end it. But then, this is dummy text. It is not meant to be read. Period.
Related Post
Types of chillers, Vapor compression cycle, Vapor Compression Water Chillers
Chilled water system,Types of Water Chillers, Vapor-Compression Water Chillers
Water chiller
What is HVAC ? What is HVAC Basics?
The Basics of HVAC – HVAC for Beginners
Basic need
of HVAC
The Objective of HVAC are to
ABSORPTION CHILLERS ,TYPES OF ABSORPTION CHILLERS
Absorption Water Chillers
So far, we've discussed water chillers that use the vapor-com
BASICS OF PSYCHROMETRIC CHART | PSYCHROMETRIC CHART IN HVAC SYSTEM
Psychrometric Chart
Many of the air-conditioning processes involve air that's experienci
ConversionConversion EmoticonEmoticon