Air conditioner

Air conditioner definition:

A system for controlling the humidity, ventilation, and temperature in a building or vehicle, typically to maintain a cool
atmosphere in warm conditions.

01 . CLASSIFICATION OF AIR CONDITIONING SYSTEMS

Basic Approach
Because of the variation in building occupancies as well as the outdoor weather in various locations, and because of
different operating requirements from facility developers, owners, and users, air conditioning or HVAC&R systems
are usually designed, installed, and operated in different types and configurations, with different system
characteristics to meet these requirements.

The purpose of classifying air conditioning systems is to distinguish one type from another and to provide a
background for the selection of an optimum air conditioning system based on requirements. As each air condition
system consists of air, water, heating, and refrigeration systems, the classification of air conditioning systems and is
often mixed with the classification of air systems and water and refrigeration systems. If a designer cannot properly
classify an air conditioning system and distinguish it from others, it will be difficult for him or her to select an
appropriate system for the client.

During the classification of air conditioning systems, the following points should be considered:

 The classification of air conditioning systems, or HVAC&R systems, should include the primary aspects of
air systems as well as heating and cooling systems if possible, as the air system directly affects the control of
the indoor thermal environment and indoor air quality.
 The system and the primary equipment used should be compatible with each other. For example, the primary
equipment in a unitary packaged system is the packaged unit.
 System classification should mainly be based on practical applications. For example, as the indoor air quality
becomes one of the primary criteria used to select an air conditioning system, it must be considered whether
an “all-water system” without outdoor ventilation air supply can exist.
 System classification should be simple, and each of the air conditioning systems should be clearly different
from the others.
02. Air Conditioning Systems Classification
As discussed in Chap. 1, air conditioning systems can be classified currently into eight categories according
to their configurations and operating characteristics:
 Individual room air conditioning systems or simply individual systems
 Evaporative cooling air conditioning systems
 Desiccant-based air conditioning systems or simply desiccant systems
 Thermal storage air conditioning systems or simply thermal storage systems
 Clean room air conditioning systems or simply clean room systems.
 Space conditioning air conditioning systems or simply space systems
 Unitary packaged air conditioning systems or simply packaged systems
 Central hydraulic air conditioning systems or simply central systems
First, as discussed in Sec. 1.5, the individual, space, packaged, and central systems together had more than 98 percent of floor
area both in commercial buildings in 1992 and in air conditioned homes in 1991 in the United States. Clean room and desiccant-
based air conditioning systems are often processed air conditioned systems. Except where deep-well water or an air economizer
is available, evaporative cooling systems are the cheapest cooling systems and are widely used in arid southwestern areas of the
United States. Thermal storage systems have a quite different water system and operating characteristics from a central system.
Second, there are many specific air conditioning systems used in many industrial applications such as air conditioning used for
textile mills with air washers, and also new air conditioning technology will be invented and developed. As soon as their
importance and their distinct system characteristics are recognized by the HVAC&R industry, a new category of air conditioning
system should be added.

Air, Heating, and Cooling Systems Designation

The title of air conditioning systems listed in later sections of this chapter and succeeding chapters, such as VAV reheat
rooftop packaged systems, also designates the air, heating, and cooling systems:
A packaged system always has a cooling system that uses the DX coil to cool air directly. A desiccant- based system usually
uses the DX coil as supplementary cooling. An individual system also uses a small, self-contained, factory-assembled
refrigeration system that has a DX coil to cool air.
A central system has a cooling system that uses chilled water as a cooling medium to cool air indirectly. A thermal storage
system is always a central system that uses chilled water or brine as the cooling medium.
As discussed in Sec. 9.18, for DX coils in individual systems, rotary compressors are the most widely used. For DX coils in
packaged systems, reciprocating and scroll compressors are most widely used. Scroll compressors are gradually replacing the
reciprocating compressors in packaged systems because of their higher energy efficiency. For chillers in central and space
systems, centrifugal and screw compressors are widely used in large chillers whose cooling capacities are greater than 75 tons
(264 kW); and screw, scroll, and reciprocating compressors are widely used in medium-size and small chillers. Screw and scroll
types are also gradually replacing the reciprocating compressors in small and medium-size chillers.
As discussed in Sec. 8.1, hot water, heat pump, and direct-fired warm air furnace heating systems were installed in commercial
and residential buildings with a floor area of both about 75 percent in the early 1990s. In packaged systems, direct-fired warm
air furnaces and heat pumps are often used.
For individual systems, either heat pumps or electric resistance heaters are often used. In central and clean space systems, hot
water heating systems are most widely used. As discussed in Sec. 20.9, air systems can be classified into three categories:
Constant-volume (CV) outdoor recirculating air mixing systems Variable-air-volume (VAV) outdoor recirculating air mixing
systems:
Dedicated ventilation and space recirculating systems only air systems of the space air conditioning systems are dedicated
ventilation and space circulating systems. Individual, packaged systems in residential and clean room air conditioning systems
are mostly CV air systems. All the other air conditioning systems may be either CV or VAV systems and will be so designated.

What is the Inverter technology in air conditioners?

An Inverter is used to control the speed of the compressor motor, so as to continuously regulate the temperature. The DC
Inverter units have a variable-frequency drive that comprises an adjustable electrical inverter to control the speed of the
electromotor, which means the compressor and the cooling / heating output.

The Inverter technology (DC) is the latest evolution of technology concerning the electro motors of the compressors. An
Inverter is used to control the speed of the compressor motor, so as to continuously regulate the temperature. The DC Inverter
units have a variable-frequency drive that comprises an adjustable electrical inverter to control the speed of the electromotor,
which means the compressor and the cooling / heating output. The drive converts the incoming AC current to DC and then
through a modulation in an electrical inverter produces current of desired frequency. A microcontroller can sample each
ambient air temperature and adjust accordingly the speed of the compressor. The inverter air conditioning units have
increased efficiency in contraction to traditional air conditioners, extended life of their parts and the sharp fluctuations in the
load are eliminated. This makes the inverter AC units quieter, with lower operating cost and with less broke downs. The
inverter AC units might be more expensive than the constant speed air conditioners, but this is balanced by lower energy bills.
The payback time is approximately two years depending on the usage.
What is the power consumption of inverter AC?

For 1 ton AC inverter, power consumption of ac = cooling capacity/EER = 1.5*3.517/2.7=1.954 kW. AC consists
of two units, Indoor unit which is called the evaporator and the Outdoor Unit which called the Compressor. The
power consumed by the evaporator is very less as compared to the compressor.

How does an inverter air conditioner work?

Contrary to this , in an inverter air -conditioner the compressor can work on part-load conditions as well . ... An
inverter in an air conditioner is used to control the speed of the compressor motor to drive variable refrigerant
flow in an air conditioningsystem to regulate the conditioned-space temperature.

How much power is consumed by 1.5 ton AC?

cooling capacity of 1 ton is equal to 3.517 kW of power.
For 1.5 ton AC ,power consumption of ac =cooling capacity/EER.
=1.5*3.517/2.7=1.954 kW.
AC consists of two units, Indoor unit which is called the evaporator and the Outdoor Unit which called the
Compressor.

cooling capacity/EER
A room air conditioner's efficiency is measured by the energy efficiency ratio (EER). The EER is the ratio of the cooling capacity
(in British thermal units [Btu] per hour) to the power input (in watts). The higher the EER rating, the more efficient the air
conditioner.