The first question to answer when selecting the most appropriate heating or cooling system is whether to include heating, air conditioning, or both. Although air conditioning is a common need in most places today, this can be effectively addressed by considering design and construction requirements, behavior, and other factors such as dehumidification in humid climates (Devoe 2012, p. 356).
Where buildings are to the right standards, the heating system can sometimes be eliminated, allowing the buildings to be heated only by the excess heat produced by occupants and electric equipment.
Ordinarily, homes that require air conditioning must use some type of air distribution system, while those that require only heating have tend to have more options which include both air and radiation distribution (Chiras 2012, p. 13). Understanding the pros and cons of each type of distribution system is very helpful in determining the most appropriate system tom purchase. Other considerations are equipment efficiency, available fuel sources, and the occupants’ preferences.
This paper discusses three types of air conditioning systems and three types of heating systems and suggests, with reasons, the best options from the systems presented.
When choosing a heating system, most people tend to focus more on getting the best modern systems, forgetting that the important thing is to select the type that fits their mode of living, existing climate and type of house. In many homes today, for instance, no one is left in the house during the daytime, when every one is at work.
In a case like this, what is needed is a system that will give quick heat as soon as it is started in the evening. Such systems include steam and warm-air systems. For a household where the care of the heating apparatus is left to the women members during the day, it is desirable to have a system that uses hot water or vapor and one that can maintain a steady supply of heat without requiring so much attention.
In homes where it is the custom, at least once in a while, to close everything up and take a vacation, a warm-air system proves particularly advantageous as there is nothing to freeze. It is also important to consider whether the shape of a house and prevailing weather conditions should form part of the criteria in the selection process of a heating system.
Steam heat, for instance, is not the best choice for a mild and unchanging climate. Ideally, steam heating systems are suited for erratic, up and down temperatures. In general, people with a compact house of moderate size, are in a better position to use a warm-air system than those with a large, rambling dwelling.
To make the best choice, therefore, a careful examination of the necessary requirements, and not only of the advantages and disadvantages of each type of system and its suitability for the particular environment, is critical. Depending on the type of distribution system selected for a house, a variety of heating systems are available. Forced air systems, hydronic floor systems, and electric radiators are among them and are discussed below.
Forced Air Systems
According to Binggeli (2011, p. 216), forced air heating system is the most versatile and widely used system for heating houses and small buildings. The system usually burn gas or oil inside a closed heat exchanger to heat the air. The system can include heating, cooling, humidification, dehumidification, and filtration. It provides the least expensive way to distribute heat throughout the house and responds quickly to temperature changes.
A forced air system can, however, cause pressure imbalances and bring pollutants into the house when not properly designed and sealed. An oversized air conditioning system can be inefficient and does not have the ability to properly dehumidify. If not well positioned, some areas of the house can be obstructed by furniture. In addition, a forced air system can be extremely noisy and the noise generated can be transferred between rooms through ducts.
Hydronic Floor Systems
Hydronic floor heating systems heat water and propel it through tubes in order to generate heat (Brumbaugh 2004, p. 6). Generally, the systems can classified as wet or dry installations based on how they are designed.
For wet installations, the tubes are normally placed inside foundation slabs and then enclosed in a further layer of concrete to provide some form of reinforcement. For dry installations, however, no tube is enclosed in concrete.
Hydronic floor systems provide heating with lower temperatures than radiators, warm people more than spaces, offer comfortable heating, are quiet, and do not cause pressure imbalances.
However, they are slow in responding to temperature changes, can only supply heating services, and do not allow air filtration. Furthermore, hydronic cooling systems are rare and are generally only effective in climates with limited cooling needs where the temperature of water can be maintained below the dew point to avoid condensation (Devoe 2012, p. 359).
According to Linsley (2011, p. 413), electric radiators can generally be classified into two major groups. On one hand are the unrestricted local heating systems provided by portable electric radiators which plug into the socket outlets of the installation while on the other hand are off-peak heating systems that provide central heating from storage radiators, ducted warm-air, or under-floor heating elements.
According to Devoe (2012, p. 359) electric radiators respond quickly to temperature changes, are quiet, and do not cause pressure imbalances. However, like hydronic floor systems, they can only supply heating services and do not allow air filtration. They are also more expensive and can easily interfere with furniture placement in a house. Moreover, radiators covered with furniture are incapable of heating effectively.
In general, electric radiators can be very effective for super insulated homes that require very little heating. They may also be powered by on-site renewable electrical generation.
Air Conditioning or Cooling Systems
The type of cooling system best suited for a home depends on a number of factors which include the cost to purchase, install, operate, and maintain the equipment as well as the level desired of efficiency (Carroon 2011, p. 241). In the United States, it is common most new homes to be built with some form of air conditioning.
Since almost all cooling systems are fueled by electricity, and most homes require heating as well as air conditioning, the cooling system decision often follows the heating system decision. Forced air cooling systems, hydronic radiant cooling systems, and hydronic fan coil systems are discussed in the following sub sections.
Forced Air Cooling Systems
Forced air cooling systems are available as split systems or packaged units. Typically, when a distributed cooling system is installed, it is either a heat pump or an air conditioner partnered with a central furnace and a shared channel (Goswami & Zhao 2009). The air handler should be centrally located to reduce duct run-length, but also placed near the outdoor condensing unit to limit the length of the refrigerator line.
To perform efficiently, condensing units require adequate air flow. Generally, this entails keeping all obstructions including fences and shrubs a minimum of 2 inches away from the sides of the unit so as to create enough space to effectively release heat. Shading from direct sun with trees also helps to increase efficiency. When a forced air cooling system that does not provide heat is installed in an unconditioned area, the registers should be designed in such a way that they can be easily sealed during cold weather.
Forced air cooling systems operate by forcing pre-chilled air through a system of hoses worn close to the body. The cooler air that goes by the skin is responsible for create comfort to people and provides the link between the human body and the external environment. To a large extent, these systems are lightweight and provide long term cooling benefits.
Mobility is, however, limited because the hose is attached to an external fixed compressor (NFPA 2008, p. 857). As stated earlier, forced air systems provide the least expensive way to distribute conditioning and respond quickly to temperature changes. Unfortunately, oversized air conditioning systems can be inefficient and do not have the ability to properly dehumidify.
Hydronic Radiant Cooling Systems
Unlike a conventional system that uses chilled air and duct work, hydronic radiant cooling systems rely on chilled water pipes to distribute cooling throughout a building. With the help of pipes laid out in the ceiling, radiant cooling systems are able to ensure that a cool atmosphere exits (Allen & Thallon 2011).
Subsequently, people seated in a room are kept cool. The radiation system is designed to absorb the heat generated by those in the room. The system effectively regulates the temperature in the room to eliminate condensation.
Separate ventilations are also used to help manage the level of humidity in the room. Given that it is generally easy to control the flow of water, the process of managing the home is greatly simplified. As pointed out earlier, hydronic radiant cooling systems are rare and generally only effective in climates that have limited cooling needs.
Hydronic Fan Coil Systems
Hydronic fan coil systems have the ability to combine both heating and cooling and to respond quickly to temperature changes. They, however, do not allow air filtration and can create so much noise. In addition, they are characterized by high installation costs and are uncommon in residential applications. Another challenge is that wall mounted units are easily affected by furniture (Weiss 2003, p. 199).
Based on the preceding discussion, it is obvious that forced air systems are the best for both heating and cooling purposes. Unlike the other types of systems, forced air systems have the distinct advantage of combining several key functions which include heating, cooling, humidification, dehumidification, and filtration services.
With the exception of hydronic floor systems and hydronic fan coil systems, electronic radiators are quite limited in operation and can only provide heating services. However, hydronic floor systems and hydronic fan coil systems are equally limited by climatic conditions and temperature.
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