a reversible air-conditioner, heat pump warms and cools - in a heat pump

by:HICOOL     2019-09-01
a reversible air-conditioner, heat pump warms and cools  -  in a heat pump
WALDJULY 1991 this is a digital version of an article from The Times Print Archive, before it begins online publishing in 1996.
To keep these articles as they appear initially, the Times will not change, edit, or update them.
There are occasional copywriting errors or other problems during the digitization process.
Please send a report of such issues to archid_feedback @ nytimes. com.
In the past, the heating and cooling of the house was a separate job, but the heat pump, a device that usually costs a lot less, is becoming more and more popular.
According to recent government estimates, nearly one out of every three new homes in the United States uses a heat pump;
Heat pumps are almost common in new homes in some parts of the country.
Heat pump "is nothing more than a glorious air --
"Air conditioning," said Robert M. Little Sr.
Head of the residential marketing department at Tampa Electric Power, Florida.
Because it is reversible, it is glorious.
It's like a central air conditioner in summer.
The air conditioner, whose condenser absorbs heat, and discharges it outdoors.
In winter, it collects heat from the outside and pushes it inside.
One might wonder how a machine can draw heat from a cold place and put it in a warm place, but that's exactly the normal air --
When the air conditioner reduces the indoor temperature to 75 degrees and sends the Heat into 90 degrees, it does soOutdoor degree. An old-
When the coil resists current, the old-fashioned electric heater converts electricity into heat.
When the outdoor temperature is 50 degrees, the heat pump will only use the same power as the third resistor heater to heat the house to 68 degrees.
For example, Sir.
Few say a typical house in Tampa will use 6,000 KW
Heat-resistant hours a year, but only 1,440-
It will take several hours if it has a heat pump.
The farther north, the smaller the difference;
North of Washington, it dropped to near zero.
In the Washington area, some people use heat pumps and conventional gas for most winter months-or oil-
Despite the higher cost of capital for this combination, the system was fired in the coldest days.
Jack Stevenson, manager of residential energy services at Potomac Electric Power, described a case where another house might have both.
Some houses are too big for one person.
He said that due to the length of the pipe, the air system.
The solution favored by builders is to install a second system in the attic;
Heat pumps are preferred for safety reasons.
In most parts of the country, the main competitor of heat pump heating is a very high advertising
High efficiency gas burner.
The heat pump introduced 30 years ago caused some complaints, especially the early models.
They can be noisy, produce drafts, and do not remove humidity.
Recent changes have reduced these issues and reduced operating costs.
However, heat pumps are limited by climate.
Their biggest drawback is that as the outdoor temperature drops, collecting enough heat to help the room need more and more electricity.
Under 30 degrees Fahrenheit, heat pumps usually require the help of a resistor heater, and heat pumps below 15 degrees are almost useless.
In addition, when the outdoor temperature is below freezing point, the moisture in the air will form ice on the heat pump coil, a bit like the old-
Vintage refrigerator
Refrigerator, reduce efficiency.
The heat pump solves this problem by heating the coil, which also reduces the efficiency.
Millions of homes use resistance heaters, but their operating costs are often much higher than alternatives such as natural gas, heating oil, or propane.
The amount of electricity used by the heat pump is critical because installing a heat pump is 10 to 25% more expensive than installing an electric air
Air conditioning and traditional gas stove.
According to the Department of Energy, in areas where temperatures are often below 25 degrees, the heat pump requires so much supplemental resistance heat that it may not make sense.
In places where heat pumps are economical, power companies are usually eager to see them installed, so local power companies are a great place for homeowners to start asking.
Many utilities will estimate the size of the heat pump needed and calculate the operating costs.
But the installation is usually done by the owner's contractor.
To improve power efficiency, some utilities offer rebates to people who install heat pumps.
For example, coollina Power & Light will lend customers money to buy heat pumps and will lower interest rates for particularly efficient models.
Carolina power and other utilities have found it cheaper to subsidize the purchase of efficient appliances than to build new power plants to supply inefficient appliances.
Efficiency of heat pump--
That is to say, the amount of temperature change it generates per unit of electricity consumed--
Changes with outdoor temperature and desired indoor temperature.
The government requires the use of a standard called Seasonal Energy Efficiency ratio to mark a heat pump, a measure that combines efficiency levels under all conditions. (
A related measure, energy efficiency ratio, used in conventional air-conditioners. )
Check with your power company before purchasing from a private contractor;
Many utilities pay rebates if the heat pump reaches the minimum efficiency standard.
The new heat pump design is much more efficient than the old one.
One reason is that most designs run at variable speeds to keep the indoor temperature at the desired level while conventional air-
The air conditioner or stove runs for a period of time so that the House reaches the proper temperature and then closes until the temperature deviates from the desired range.
Continuous operation means higher efficiency and eliminates the features many homeowners consider objectionable, that is, cold air in the pipe at startup --up.
In Carolina power and elsewhere, heat pump experts stress that a good heat pump system must be considered to work properly.
Forced House
Air heating using natural gas is not always a good choice for conversion, as the existing hot air system will heat up to about 120 degrees of air blowing.
The heat pump may produce only 90 degrees or 100 degrees, so it must pass more air through the pipe at a higher speed, which may cause howling.
The new heat pump is designed to produce higher-
The temperature of the air, which may also be key.
In winter, air below the body temperature creates a airflow that feels cold, even if it is warm enough to raise the room temperature to the desired level.
Another key issue is scale.
If the heat pump is too large, it doesn't have to work very hard in order to cool the house, but there is a downside to this.
When the humidity passes through the cold coil, it is removed from the air, but if the system is too large, it will lower the temperature before all the air has a chance to pass through the coil, keeping the house cool but damp.
A version of this article was printed on page 1001048 of the National edition on July 27, 1991 with the title: a reversible air
Air conditioning, heat pump heating and cooling.
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