Heating, ventilation and air conditioning (HVAC) in the home has a few principal functions. These principles include controlling the temperature, the humidity, and maintaining the atmosphere quality. Heating and cooling systems are classified into two groups: Central and local systems.
Central System
The central system is the most standard method for controlling the temperature in the home. It produces warm or cool air in one central area and then distributes it throughout the house. They may be either radiant or forced air. It is most commonly a central AC unit, as well. Some examples of central HVAC schemes include heat pumps, gas and oil furnaces, evaporator coils, and air conditioners.
Heating Using Central System
Heating units provide welcomed warmth to the home especially in cold climates. They are either radiant or forced air heating systems.
Radiant systems work by transferring heat from heated water or steam that is circulated through an arrangement of radiators or exchangers. The radiators transfer heat to the area or room by convection and not radiation.
Forced air central heating operates by heating an exchanger (usually a furnace) either by hot water, gas, electricity or oil. Air is forced to pass over or through the exchanger that warms the atmosphere. The hot ventilation circulates through sheet metal ducts which run into each room or area by registered vents. Read entire article.
In this environmentally friendly world that we all live in certain steps have to be taken to ensure that there is still a world for people to inhabit in the future. People all over the world are looking at ways to help save energy and the world’s resources. Household heating is a major consumer of energy so whatever can be developed to reduce the effect on the environment has got to be a step in the right direction.
By extracting heat from the ground or air (geothermal energy) and then compressing it to raise the temperature significantly, the heat generated can then be used for water or space heating.
Since there is quite a lot of heat energy in even very cold materials, heat pumps can use sources that appear to be very unpromising. For example, if the temperature of the air is 5°C, that might appear to be too cold to extract any heat. In reality 5°C is pretty hot compared to absolute zero (-273°C) and therefore an air source heat pump can produce useable heat all year round. Think of your deep freeze. Heat continues to be extracted from that area even though it’s well below freezing.
Heat pumps can use air, water and, increasingly commonly, the ground below your feet as a source of energy. Ground water is a particularly useful source of heat since it rarely gets much colder than 7°C.
Unlike more conventional heating or air conditioning, heat pumps minimise pollution and fuel use. By utilizing entirely free and renewable geothermal sources of energy they are very low carbon and very economic to run. During hotter summer months the latest models can even be run in reverse to passively extract heat from inside a home and ‘dump it’ into the ground. This method of cooling is one of the lowest carbon and lowest energy approaches available.
For every unit of electrical power needed to extract the heat, up to six units of heat can be obtained. That’s right, heat pumps can be up to 600 per cent efficient. It’s like buying a low-energy light bulb with an output rating of I00 watts but with an energy usage of only 20 watts. Remember, we spend very little on electricity for light bulbs in our homes compared to running our heating and hot water systems – so the savings are much greater.
The attraction of running a heating system this efficiently is obvious. It saves money and makes a real contribution towards a low or even zero carbon building and towards reducing the devastating impact of climate change. It’s worth recalling how, by 2016, every new home in the UK will need to be rated ‘zero carbon’. Given that the law in this area is getting tougher all the time and the 2016 date is now fixed, new business opportunities are growing rapidly.
More and more heat pumps will be installed in the coming years which can only be good news for the environment. Pioneering companies have already gotten to grips with issues around the ground works required and enterprising trades people are discovering how they can become part of the future of our industry.
The next generation of heat pump technology that is even easier to install, and operate further reduces running costs and improves the already impressive efficiency which will make the models of the future even more appealing to the mass market. These will offer air, water and ground source heat pumps to suit all household heating needs, helping to reduce the cost of heating water for your bath as well as heating the whole house during the colder months. In addition to being powerful systems in their own right the heat pumps of the future even come ready to connect to a solar heating system, complete with flat-panel collector array and solar cylinder, providing an integration of solar energy and heat pump for domestic hot water and central heating.
Heat pumps will make a huge difference to the way we heat our homes as well as making a big difference, for the better on the environment.
By: Harwood E Woodpecker
Many older homes were built pre-central heat and air. This is a luxury that many of us have to enjoy and when moving into an older we find that this luxury is also a necessity. We tend to lose tolerance for heat as we grow older and those old window air conditioning units just look tacky. However, the whole idea of having to add ducts to a home can sound difficult and expensive, but it is easier than you might think.
Central heat and air uses a primary heating appliance such as a furnace that is often located in an area such as a small closet, basement or garage. These systems deliver heat throughout the house through pumped warm air through a system of air ducts or by sending hot water or steam through pipes to room radiators. In newer homes, the system is usually built in with the home. The duct system may be set up with an air conditioner, heat pump, or furnace. There are also two types of systems including a forced air system and a gravity system. Gravity systems, however, do not provide air conditioning and can only provide heat. If your system includes an air conditioner, then the system is a forced-air system.
Air conditioners and heat pumps are forced air systems that share ductwork. The air conditioner runs on electricity and removes heat from air through refrigeration. The heat pump is capable of providing both heating and cooling. In the winter, the heat pump extracts the heat from outside air and delivers it into the home. In the summer it does the opposite. It extracts the cool air and pumps it into the home. These systems tend to be very economical and use only one duct system.
Many central air conditioners are split systems with a condenser outside and the fan and coil unit mounted in the attic. This means that the ducts will originate in the attics. The challenge here is if the home is two stories. It can be difficult to get the supply and return ducts to the first floor. The second floor will generally have ducts that run through the attic floor, while the first floor will need to have ducts run through closets. This takes up less space than some may think and the mess can be minimal. The contractor will need to cut holes in the first and second floor ceilings and some second floor closets will need to be used for running ducts.
This work will be well worth it in the long run when your home is kept cool in the summer and warm in the winter. If you have an older home, especially one with two stories, it can be difficult to spend anytime upstairs during the summer. The upstairs rooms will hold a large amount of heat and will definitely benefit from central heat and air. In the winter it is often difficult to keep first floors warm because the heat rises. Central heat will make your first floor rooms much more comfortable.
By: Christopher Brown