Air condition
Air Conditioning Psychrometrics
Course No: M05-005
Credit: 5 PDH
A. Bhatia
Continuing Education and Development, Inc.
9 Greyridge Farm Court
Stony Point, NY 10980
P: (877) 322-5800
F: (877) 322-4774 info@cedengineering.com AIRCONDITIONING PSYCHROMETRICS
AIR CONDITIONING PSYCHROMETRICS
In air-conditioning system, the air must undergo one or several of the following processes: Psychrometrics can be used to predict changes in the environment when the amount of heat and/or moisture in the air changes. Use of psychrometric analysis is also important to determine the volume flow rates of air to be pushed into the ducting system and the sizing of the major system components.
Approaches to Temperature Control
Temperature control in an air conditioning system is achieved by passing the air through the cooling or heating coil, which may use any of the following approaches:
1. Vary the temperature of air supplied to the space while keeping the airflow rate constant. This is the basic constant volume, variable temperature approach.
2. Vary the airflow rate while keeping the temperature constant for air supplied to the space. This is the variable volume, constant temperature approach.
3. Vary the airflow rate and change the temperature for air supplied to the space. This is the variable volume and temperature approach.
4. Vary both the supply air temperature and flow rate where the airflow rate is varied down to a minimum value, then energy input to reheat the coil is controlled to vary the supply air temperature. This is the variable volume reheat approach.
Approaches to Humidity Control
Humidity control in a conditioned space is done by controlling the amount of water vapor present in the air in the space. When relative humidity at the desired temperature set-point is too high, dehumidification is required to reduce the amount of water vapor in the air for humidity control. Similarly, when relative humidity at the
desired
Course No: M05-005
Credit: 5 PDH
A. Bhatia
Continuing Education and Development, Inc.
9 Greyridge Farm Court
Stony Point, NY 10980
P: (877) 322-5800
F: (877) 322-4774 info@cedengineering.com AIRCONDITIONING PSYCHROMETRICS
AIR CONDITIONING PSYCHROMETRICS
In air-conditioning system, the air must undergo one or several of the following processes: Psychrometrics can be used to predict changes in the environment when the amount of heat and/or moisture in the air changes. Use of psychrometric analysis is also important to determine the volume flow rates of air to be pushed into the ducting system and the sizing of the major system components.
Approaches to Temperature Control
Temperature control in an air conditioning system is achieved by passing the air through the cooling or heating coil, which may use any of the following approaches:
1. Vary the temperature of air supplied to the space while keeping the airflow rate constant. This is the basic constant volume, variable temperature approach.
2. Vary the airflow rate while keeping the temperature constant for air supplied to the space. This is the variable volume, constant temperature approach.
3. Vary the airflow rate and change the temperature for air supplied to the space. This is the variable volume and temperature approach.
4. Vary both the supply air temperature and flow rate where the airflow rate is varied down to a minimum value, then energy input to reheat the coil is controlled to vary the supply air temperature. This is the variable volume reheat approach.
Approaches to Humidity Control
Humidity control in a conditioned space is done by controlling the amount of water vapor present in the air in the space. When relative humidity at the desired temperature set-point is too high, dehumidification is required to reduce the amount of water vapor in the air for humidity control. Similarly, when relative humidity at the
desired