Energy Efficiency: Resource Reports

Air-to-Air Heat Exchange   

An air-to-air heat exchanger, also called Air-to-Air Energy Recovery Ventilation Equipment (AAERV), is one type of HVAC  system becoming more popular in “green” building.  There are several different types of heat exchangers, but they all have one main idea behind them:  take energy from “used” warm air coming from the occupancy space and put it back into cold “unused” air which is going back to the occupancy space.  One method of heat exchange is by using a heat pipe heat exchanger.  This is a system which has tubes in the ventilation system with fluid inside of them.  The energy is transferred by the fluid evaporating by taking the energy from the warm return air, and transferring that energy to the incoming air by condensation.[i]  Other forms include plate heat exchangers and rotary heat exchangers. 

ENERGY STAR®

ENERGY STAR®  is a widely recognized government supported program that works with industries to provide energy-efficient, cost-effective solutions for consumers.  The ENERGY STAR® label is awarded to products that fulfill strict energy criteria offering the features and performance consumers want as well as providing payback if initial costs are higher. 

ENERGY STAR®  was started by the U.S. Environmental Protection Agency (EPA) in 1992 for energy-efficient computers.[ii]  The program expanded and four years later it partnered with the U.S. Department of Energy (DOE).  Today, ENERGY STAR® continues to grow, covering more the 40 product categories for home and office.[iii] 

The EPA and the DOE work closely to ensure the integrity of the ENERGY STAR®  label.  Products are selectively tested and routinely monitored to prove they are meeting requirements .  Also, performance criteria are regularly updated to match the most current, most efficient products.  All funding for ENERGY STAR® is put towards educational booklets and programs for businesses and homeowners.  Striving to “break down major market barriers and alter design making for the long-term,” ENERGY STAR® realizes an important mission.[iv]  Although there is still a long way to go, the savings are adding up.  In 2002, ENERGY STAR® helped Americans save enough energy to power 20 million homes.[v] If you have not seen the label, start looking for it.

Mechanical Systems  

Mechanical systems, in reference to buildings, are those systems which play some role in controlling the environment  within the building during the occupancy phase.  The most commonly referred to mechanical system would be the Heating, Ventilation, and Air Conditioning (HVAC ) systems.  This system typically uses the most energy in a building, so by trying to save energy in this part of a building, one can significantly make the building more efficient. 

Renewable  Resources

Renewable  energy resources are often called renewable natural energy resources.  It is a way of taking energy from the earth and its environment  without actually depleting resources.  Renewable energy comes from resources that are always present, like the sun, wind, and geothermal activity. 

We are able to capture energy from the sun in two different ways:  passively and actively.  Passive solar energy is simply using the suns rays to heat a building by allowing the sun to enter the building through the use of daylighting  techniques.  Typically, buildings that are incorporate passive solar heating techniques have larger windows  on the south side of the building to allow the greatest amount of sun to enter the room.  They often use building materials that absorb the sun’s energy and release it slowly back into the building in the form of heat.[vi]  Using passive solar heating techniques properly can reduce heating bills quite drastically, in some cases, up to 50 percent.  Active solar techniques, unlike passive, involve using mechanical means to produce electricity.  Photovoltaic cells, (PV cells), use the movement of electrons created by the sun’s energy to create electricity.  PV cells can be arranged in smaller numbers to provide energy for small building, or they can be arranged in very high numbers to create a solar power plant.  Solar water heating is also a very common active solar energy resource.

Wind power is a renewable  resource which was started abroad, but has just recently begun to gain popularity in the U.S.  It is estimated that if all the land that has been calculated to produce the best wind power, (based on flatness of land and availability of wind), was used in the U.S. for wind power, we could produce about 15 percent of the nation’s electricity demand.[vii]  We could also do this by not producing any wastes or depleting any resources.