Table of Contents
- 1 How do you control the temperature of a heat exchanger outlet?
- 2 Do control valves go on supply or return?
- 3 What is heat Interchanger?
- 4 Why are there two way valves on return lines?
- 5 What is thermostatic temperature control?
- 6 Where is the heat exchanger located in a furnace?
- 7 Can a control valve be provided at the inlet and outlet?
- 8 How is the temperature of a heat exchanger measured?
How do you control the temperature of a heat exchanger outlet?
To control the outlet temperature of heat exchanger system closed loop control is required which can be achieved by a controller. The control algorithm considered to achieve the desired control objective are Proportional-Integral-Derivative (PID) control, feed forward controller and internal model controller.
Do control valves go on supply or return?
Shifting viewpoints on flow controls can cause disagreements where balancing valves should be located in closed loop systems. Many (including us at Hays Fluid Controls) agree that the balancing valves should be placed on the return side, whereas other companies may choose the supply side.
Why are control valves on the return side?
Most agree (including those of us at JMP) that flow balancing valves should be placed on the return side of coils whenever possible. Compared with placement on the supply side, flow balance valves on the return side will reduce the amount of free air in the coil and thus the potential for noise.
How does a temperature control valve work?
A valve that is actuated by internally sensing and controlling the fluid temperatures is called a thermostatic valve. As the temperature of the fluid changes, it causes the wax to expand or contract which, in turn, slides the valve up or down, opening or closing ports.
What is heat Interchanger?
A heat exchanger is a system used to transfer heat between two or more fluids. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contact. Heat exchangers are used in both cooling and heating processes.
Why are there two way valves on return lines?
Short answer: use 2 way control valves (allows the water to only flow one way at one time) for lines controlled by smaller/fewer pumps. These are not suggested for chilled water lines.
How does a balance valve work?
Dynamic balancing valves work as flow limiters. They are set to a desired flow rate and ensure that a larger flow rate does not take place. If the pressure in front of the valve increases, it will close some more, so the pressure loss across the valve becomes correspondingly higher.
What is the function of DRV valve?
A DRV is utilized in plumbing to control water temperature and are widely used in showers. Double regulating valves are pressure sensitive and they react to pressure changes from the hot and cold water flowing into them. It causes the valve to either open or closes a port, thus maintains a pressure balance.
What is thermostatic temperature control?
Thermostatic temperature control systems consist of a thermostat plus some sort of heater and/or cooler. If temperature is below the set point, the heater is on and the temperature rises. When the rising temperature passes the set point, the thermostat switches the heater off and temperature falls passively.
Where is the heat exchanger located in a furnace?
The burners in the furnace produce a flame that goes into the heat exchanger. Therefore the heat exchanger is adjacent to the gas valve and burners, in the same section of the furnace. Generally the heat exchanger and burner section are located in the section where the air exits the furnace.
How does a heat exchanger works?
Heat exchangers, metal shells and tubes, work by transferring heat from one place to another. The hot flue gas heats the metal as the gas makes its way to the exhaust outlet of the furnace. As this is happening, the hot metal heats the air circulating over the exterior of the heat exchanger.
What is a heat exchanger control valve?
Heat exchangers are a common type of closed-loop control application where both pneumatically and electrically actuated control valves can be used to regulate water, steam, and condensate. A partial graphical representation of a typical heat exchanger utilizing a control valve is shown in Figure 1.
Can a control valve be provided at the inlet and outlet?
Thus, it is always not recommended to provide a control valve at the inlet and outlet of product line for product temperature control. Cooling water is in a network supplying to many heat exchanger through out the plant for cooling purpose.
How is the temperature of a heat exchanger measured?
The resulting temperature is measured at the outlet of the heat exchanger T1 Out (controlled variable). Heating is achieved by passing steam through the tube side. The more steam passing through the tubes, the more heat is transferred to the process fluid, and vice versa.
How to prevent thermal shock in a heat exchanger?
Providing control valve at the outlet would allow continue CW feeding into the heat exchanger, this minimise the potential of sudden temperature increase and cause heat exchanger due to thermal shock. The downside is release CW into disposal network.