The Ultimate Off-Peak Cooling Systems Quiz

By: HowStuffWorks.com Contributors

The Ultimate Off-Peak Cooling Systems Quiz
Image: ValentynVolkov/iStockphoto.com

About This Quiz

Off-peak air conditioning systems will soon be coming to a home near you. Off-peak systems have been saving companies a lot of money for years by reducing energy costs and have proven their effectiveness. Leading air conditioning companies are producing residential units that can be added to your existing system. Take our quiz now to see if you are ready to cool off with off-peak air conditioning.
Who invented the air conditioner?
Aaron Friedrich
George Trane
Willis Carrier
The first air conditioner was invented by a man named Willis Carrier in 1902. He invented it to reduce heat and humidity causing smudged pages at a printing plant.

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What year was the first residential air conditioner introduced?
1928
The first home air conditioner was introduced in 1928. The unit was called the Weathermaker.
1918
1905

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What is one of the best ways that a company can save money on their air conditioning costs?
A company can increase room temperature minimums by 2 degrees.
A company can control access to thermostats with locking covers.
A company can install an off-peak cooling system.
One of the best ways to save on air conditioning costs is to switch over to an off-peak cooling system. Off-peak systems take advantage of the cheaper utility rates offered during non-peak hours.

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How does off-peak air conditioning help utilities enough for them to create attractive rates to offer during off-peak hours?
Government forced utilities to offer off-peak discounts to businesses.
Even with lower rates, off-peak air conditioning saves money for utilities.
In spite of lower rates attached to off-peak electricity, utilities still make money because they can reduce use of more expensive peak electricity and defer capital costs associated with increasing capacity. There is an excess of power available late at night because almost everyone is in bed.

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What characteristic of conventional air conditioners helps to encourage switching to off-peak systems?
Regular air conditioners use energy less efficiently as the day becomes hotter.
Conventional air conditioners use energy less efficiently as the day becomes hotter. When air conditioners work extra hard there is less time for a full cycle to take place at maximum efficiency.
The hotter it is outside the more air conditioning capacity needs to be added to maintain temperature.
Air conditioners ice up as the day gets hotter so extra units are required to maintain capacity.

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What do utilities have to do in order to provide enough electricity during peak demand periods?
Utilities have to design their systems so capacity always exceeds demand.
Utilities are forced to buy expensive power off the grid to cover peak demand.
Utilities are forced to buy expensive power off the grid in order to cover peak demand. Even worse is that some utilities activate older generating facilities during the day to cover extra demand even though these plants generate more pollution.
Utilities have plenty of capacity and use peak demand periods to make more profit.

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How can distributing energy usage over the entire day help utilities and our environment?
Moving automated tasks and air conditioning to off-peak hours reduces the need for more generating facilities.
Moving automated tasks like laundry, dishwashers and air conditioning to off-peak hours reduces the need for more generating facilities. Fewer generating facilities using fossil fuels equals a better environment.
Utilities can reduce their use of fossil fuels to generate electricity therefore increasing profits.
Spreading energy use through the entire day helps keep energy jobs in the state that you live in.

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What is different with off-peak systems that allow them to save daytime air conditioning costs?
They manufacture dry ice at night, which is an extremely cold solid form of carbon dioxide gas.
They liquefy nitrogen at night that is stored in special tanks and gives off cold when it changes back to gas.
They freeze water in special insulated tanks at night to use for daytime cooling.
Off-peak systems freeze water in special insulated tanks at night. A refrigerant such as ethylene or propylene glycol mixed with water, which is chilled to well below freezing.

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What is the term used to describe the water-freezing mode used by off-peak systems at night?
freeze cycle
charging
Once the water is frozen, the system uses very little energy to maintain the water in a frozen state until it is required during daytime cooling hours.
ramp-up

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What is another common name used for off-peak cooling systems?
vapor-compression chiller
air-cooled chiller system
thermal energy storage system
Off-peak cooling systems are also referred to as thermal energy storage (TES) systems. Until recently TES systems were only available for large institutions but newer technology has allowed smaller systems with high operating efficiency.

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Where do companies place the large tanks of water and ice that are required for off-peak systems?
almost anywhere
Nowadays tanks can be designed to be located almost anywhere. Some companies even bury the tanks underground, which provides further insulation from daytime heat.
on the top floor
in the basement

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What factor do off-peak systems depend on to make them economically viable?
cooler temperatures at night
attractive off-peak energy rates
Off-peak air conditioning systems take advantage of the electric utilities pricing structure to make them a viable alternative. With the cost of bringing more energy generation on line, this pricing structure is unlikely to change in the foreseeable future.
existing tax credits

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What is the measurement unit used to determine the size of an air conditioning system?
ergs
BTUs
tons
Air conditioning volume is sized in tons. It takes one ton to cool 12,000 BTUs in an hour or one ton to cool about 500 square feet of space in an hour.

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How much peak energy can a typical off-peak system save if it is incorporated into an existing air conditioning system in a large residential application?
a 95 percent reduction
According to Ice Energy, their Ice Bear 50 system can save up to 95 percent off your peak energy demand when integrated with your existing system. The down side in the economics is the $4,000 to $18,000 price tag for an Ice Bear system.
an 80 percent reduction
a 60 percent reduction

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What percent reduction in peak cooling demand was achieved by the Night Sky Project?
50 to 90 percent
The Night Sky Project developed a roof-mounted system using water that was spray-cooled by the night air and stored in a tank for peak period cooling. Analysis of five test systems resulted in a 50 to 90 percent reduction in peak cooling demand.
75 to 88 percent
70 to 80 percent

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ValentynVolkov/iStockphoto.com

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