Types Of Heating System:
The majority of American homes are heated with a forced-air furnace, most commonly fueled by natural gas, but also by electricity, liquid propane or fuel oil.
How a Furnace Works
A furnace works by drawing air inside a heat exchanger, where it is warmed with a flame of natural gas, propane [...]
Experts say a ceiling fan can save up to 40 percent on your summer cooling costs, and up to 10 percent during the winter heating season. In summer, ceiling fans cool the room by creating a “wind chill effect.” For example, if you had a ceiling fan in a room that was 85 degrees, the [...]
Out of all the energy spent in and around your home, the central heating system accounts for more than one-third of it. This means you’ll be spending a lot of time and money warming your home.
But before you can decide which system is best for your home, you’ll need to know the [...]
Smokey Flues
While dealing with the minimum free areas for air replacement, a not uncommon problem is that of the ‘smoky fire’ and flue gases pulled down the chimney of a gas-fired boiler when the extract units are switched on in a kitchen or public house bar.
It should be pointed out that the National Gas [...]
Approach Velocities
The pattern of the airflow as it enters an Axial flow fan is different from the pattern as it leaves. Assuming no interference from the layout of the building, or louvres on the fan, the air entry pattern is hemispherical (shaped like half a globe or sphere). By contract the pattern [...]
Air is a gas mixture composed mainly of oxygen and nitrogen with small percentages of carbon dioxide and water vapour (moisture) in varying amounts. Dust particles and bacteria area also present, and may have to be dealt with at some point in the ventilation system, depending on the nature of the [...]
A fan is simply a machine for moving air and other gases by means of a rotating impeller using centrifugal or propeller action, or both. There are four main types of fan used for general ventilation work: centrifugal, propeller, mixed flow and axial flow. Sub-division of these main types need not [...]
Wind has pressure due to its velocity. This pressure is calculated from the equation
Vp = 0.6V², where Vp is the velocity pressure in Pascals (Pa) and V = velocity, in m/s. 0.6 is a constant, derived from the density of the air, at 20°C and average RH. A fresh gale blowing at [...]
An alternative method of ventilation which has found favour with many Local Authorities and Housing Associations is Positive Pressure Ventilation. This is an extension of the intake ventilation concept (as heat recovery is a version of a combined system). This rate of ventilation is very low, half an air change per [...]
Ventilation on the basis of heat removal from rooms where some considerable temperature drop is a main factor, needs special consideration. The amount of heat produced in the room must be estimated from:
Body heat of occupants
Electrical apparatus
Other heat-producing processes
Solar heat gain through structure
The volume of air required for ventilation can then be [...]
Air conditioning includes both the cooling and heating of air. It also cleans the air and controls the moisture level.
An air conditioner is able to cool a building because it removes heat from the indoor air and transfers it outdoors. A chemical refrigerant in the system absorbs the unwanted heat and [...]
Unfortunately, many duct systems are poorly insulated or not insulated properly.
Ducts that leak heated air into unheated spaces can add hundreds of dollars a year to your heating and cooling bills. Insulating ducts that are in unconditioned spaces is usually very cost effective. If you are buying a new duct system, [...]
With energy costs increasing, more and more houses are being insulated to conserve heat.
Draught proofing, double glazing, high levels of insulation and intermittent thermostatically controlled heating systems are sensible ways of conserving heat and energy. However, the air quality in such sealed dwellings can rapidly fall to an unacceptable level, leading [...]
One creature that has had considerable publicity in recent years is the house dust mite (dermatagophydes pteronyssinus).
Often described as microscopic, these mites, (which are related to spiders), are approximately 0.3mm long when adult. This is about the size of a full stop on a printed page, but because of their lack of [...]
We balance our body heat through Radiation, Convection and Evaporation process.
Why does anyone feel limp in hot surroundings? Why is a breeze refreshing? These sensations relate very much to the efforts the body has to make to maintain its temperature. The less the effort the more comfortable we feel. Man is a warm blooded animal [...]
Life Support
In order to maintain life, the human body must be kept at a steady temperature of 37°C. Careful measurements on astronauts have shown that the normal internal base temperature varies by less than 0.3°C among different people.
Since the human body does not register temperature, wind velocity and humidity readings, per se, the question arises [...]
Humidity is the condition of the atmosphere in relation to the water vapour it contains and is a fairly complicated subject to deal with fully, but a few brief notes will help you to understand enough of the subject for our purpose.
Water vapour is always present in the air in varying amounts, the amount that [...]
Central Heating :A central heating system has a primary heating appliance such as a furnace or boiler located in an out-of-the-way spot such as a basement or garage. It delivers heat throughout the house, either by pumping warmed air through a system of air ducts or sending hot water or steam through pipes to room [...]
An individual feels comfortable when metabolic heat is dissipated at the rate at which it is produced. Extensive experimentation has shown that for an average, sedentary, lightly clothed person this occurs most readily when the air in a standard room has a temperature of 24.5°C, a relative humidity of 40%, and [...]
Ventilation can be simply described as air circulation. This is the extraction of stale, overheated and contaminated air, and the supply and distribution of fresh air in amounts necessary to provide healthy and comfortable conditions for the occupants of the space being ventilated.
As applied to homes, offices and workshops, ventilation also means the creation of [...]
What Air Is?
Air is a gas mixture composed mainly of oxygen and nitrogen with small percentages of carbon dioxide and water vapour (moisture) in varying amounts. Dust particles and bacteria area also present, and may have to be dealt with at some point in the ventilation system, depending on the nature of the job, as [...]
Human thermal comfort is the state of mind that expresses satisfaction with the surrounding environment, according to ASHRAE Standard 55. Achieving thermal comfort for most occupants of buildings or other enclosures is a goal of HVAC design engineers.Indoor Air Quality is not part of thermal comfort, but is also a key concern of [...]
Once available only to large commercial buildings, Combined Heat and Power generation (CHP) systems are now being produced on a scale that is safe, practical, and affordable to homeowners. CHP technologies, sometimes referred to as cogeneration, have provided heat and electrical energy efficiently at commercial and industrial sites for many years. [...]
Geothermal heat pumps (GHPs) are a relatively new technology that can save homeowners money. These ground-source heat pumps use the natural heat storage capacity of the earth or ground water to provide energy efficient heating and cooling. GHPs should not be confused with air-source heat pumps that rely on heated air.
Geothermal heat pumps use the [...]
Efficient and properly leak proof ducting is the most important aspect in the installation of Heating,Ventilating and Air conditioning system in a house which actually saves lot of energy and reduces our electrical bills.
Many homeowners may feel that their money is flying right out of their windows, but it may actually be their [...]
Heat Pumps are based on the thermodynamic principles that move low pressure cold air into higher pressure hot air. The advantage of heat pumps are they work very effectively in heating very cold air in a short amount of time. Most commercial heat pumps are based on the same thermodynamic principles; however, the main differences [...]
The Environmental Protection Agency (EPA) and its Science Advisory Board report that indoor air pollution is among the top five environmental risks to public health. EPA studies show that levels of some indoor air pollutants can reach more than 100 times that of outdoor air pollutants. Indoor air pollutants such as dust mites, bacteria, and [...]
Heating and cooling systems are some of the most important investments you’ll ever make in your home. Whether you’re buying a new house, renovating an old one or making an emergency purchase because “old faithful” finally conked out, there’s a lot riding on [...]
If you are looking for heating equipment for your home, there are some facts you should know. According to the U.S. Department of Energy, nearly 56 percent of the average consumer energy bill goes directly to heating and cooling. Selecting the right heating equipment can save you money in long run.
One in [...]
Heating equipment is used to provide warmth during cold weather. Typically this equipment is used indoors but some types of heating equipment can also be used outdoors as well. Some of the common types of heating equipment are packaged heating units, boilers, individual space heaters and furnaces. Each type of heating [...]