Gas Furnace Types HVAC

Gas furnaces come in a variety of sizes and can be used for different applications. By and large, the most common gas furnaces use natural gas and utilize electronic ignition. Electronic ignition gas furnaces are slowly replacing the older style standing pilot furnaces where a pilot light remained lit all the time.

Now, with the newer modern electronic ignition, gas furnaces only use gas when there is an actual call for heat. This adds efficiency because with the older standing pilot gas furnace the pilot remained on even in the summer months. While the heat produced by a standing pilot light is negligible, it is still added heat to the system in the summer when the whole purpose in the summer is to remove the heat from the system rather than add heat like a standing pilot would do.

A gas furnace is rated for efficiency by AFUE or Annual Fuel Utilization Efficiency rating. Furnaces installed before the nineties have efficiency ratings down to 60 percent efficient (or less in some cases). The AFUE ratings of gas furnaces is simply the amount of heat delivered by the gas furnace divided by the fuel used to make that heat.

This Gas Fired Unit Heater Serves a Large Open Area

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Another way to look at AFUE is to measure the amount of heat lost up the exhaust stack. If the furnace delivers 90 percent of the heat produced into the dwelling then ten percent of the heat produced is lost up the stack. Even the highest AFUE rated furnace is going to lose heat up the stack.

It is nearly impossible to get 100 percent AFUE out of any gas or oil furnace simply because all oil and gas delivered to a furnace has a small amount of moisture in it. Gas typically has a moisture content of 4 to 5 percent. Oil depends on the quality of oil purchased, how many additives used in the oil, and the integrity of the oil tank and piping system. The end result of all this moisture and additives in the fuels effects the AFUE of the furnace and is the reason why no gas or oil furnace can achieve more than 96 percent efficiency.

The original is here: High Performance HVAC

Heating with Heat Pumps

Heat Pumps can be a very economical way of heating and cooling your dwelling depending on geographical location and the cost of electricity in your area. The volatile costs of natural gas, propane, and oil has enabled these conditions where it can be cheaper to heat with a heat pump than with fossil fuels. There is a common conception that a heat pump blows cold air and while this can be true in some cases it is not true to all heat pumps.

If a heat pump is blowing cold air when in the heating mode then it needs to be looked at because there exists a problem that needs to be corrected. Even when the outside unit kicks into the defrost mode the unit should provide adequate heat to heat the zones which it serves. Again, if it is not providing adequate heat then it needs to looked at for a technical problem that needs correcting. A well designed heat pump system, working properly and efficiently, can provide competitive and economical heat for your dwelling.

Author: High Performance HVAC

Urge for Wider Adoption of Renewable Energy

The urge for wider adoption of renewable energy is emerging as an irreversible worldwide trend. Apart from looking at renewables from the environmental angle, the search for new energy sources as substitutes for fossil fuels is another reason providing the drive.

With a projected world population of 10 billion by the year 2050, the increasing global energy
demand will bring about more rapid depletion of the world’s fossil fuel reserves. The possible tightening of energy supplies in future will inevitably result in higher prices of fuels and electricity.

Renewable energy can reduce the reliance on exhaustible sources of fossil fuel. Developed countries are now making more and more investments on the development of the related technology on renewable energies. We would envisage that when those equipment and systems for harnessing renewable energies are to be produced on a massive scale, the unit price of electricity so generated could be comparable to conventional electricity generated from fossil fuels.

How Burning Fossil Fuels is Unfriendly to the Earth

The burning of fossil fuels such as coal, oil and natural gas to generate electricity releases carbon dioxide and other pollutants into the atmosphere.

Carbon dioxide is a greenhouse gas and is one of the constituents causing abnormal climatic changes and global warming. Global warming is a phenomenon of the gradual rise of the global average air temperature at the earth’s surface, due to increased insulating effect by the greenhouse gases in upper atmosphere preventing heat dissipation at the usual rate. The consequence of global warming has far-reaching impacts on our ecosystems, affecting agricultural production, and causing rise of sea level.

The burning of fossil fuels also generates atmospheric pollutants such as sulphur dioxide (SO2), nitrogen oxides (NOX), respiratory suspended particulates (RSPs), etc. Increased level of air pollutants will affect human health, with particular adverse effect on the young and the aged, as well as people with chronic health problems. Exposure to SO2 and NOX may cause impairment of respiratory functions and aggravate existing respiratory and cardiac illnesses. Similarly, RSPs are harmful to the respiratory system and at higher levels it can increase morbidity and mortality rates.

On the other hand, the fossil fuel reserves on earth have their limits. Fossil fuels, in their crude forms, are found below the earth’s crust, where they were formed under immense pressure from the remains of plants and animals in the pre-historic era. Over the past decades, human activities in pursuit of energy supply have resulted in the rapid depletion of these limited natural resources.

The shortage of fossil fuels in the not-too-distant future could seriously affect the activities of all walks of lives and impede economic development, and could eventually cause a global degradation of living standard to every economy. The development of renewable energy technologies has become one of the prerequisites in ensuring a sustainable future for mankind.