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A cylinder contains 0.2m3 of steam at 7.0 bar.The mass of the steam is 0.8 kg. determine (a)The specific internal energy (b)The change in total internal energy if the steam is heated at constant pressure until it is dry saturated.

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May want to try this web site, they are good...

http://www.physicsforums.com/archive/index.php/t-232725.html

Posted on Oct 14, 2008

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How can I turn on the energy saver on my LWHD2400HR air conditioner? There is no switch on the A/C, only an indicator light that says "Energy Saver"?


The Energy Saver mode is activated by using the hand held remote control, that comes with the unit. Pressing the Energy Saver button activates it. Once activated the fan will shut OFF when the the compressor does. After which, about every 3 minutes the fan will turn ON to check the room air to determine if cooling is needed.

It sounds like, you're missing the hand held remote control?

Jul 19, 2011 | LG LWHD2400HR Wall/Window Air Conditioner

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I need to replace my ac but my furnace works fine. Do they need replaced at the...


Think of your air conditioner and furnace as part of a total system. That system will work better, longer and more efficiently if all of its components are matched in capacity and efficiency. By the same token, a mismatched system-one that mixes old technology with new-could decrease system performance and overall comfort.<br />For example, your new air conditioner will be capable of reaching a certain SEER efficiency rating. Because SEER is determined by a complete system combination, if your existing furnace and indoor coil are older or don't match in efficiency and capacity, you might not get the efficiency level you paid for or be able to receive accurate information on what your rating actually is. Plus, an older indoor coil may even be dirty and clogged with particles, meaning more energy will be required to push air through the system.

on Mar 27, 2011 | Air Conditioners

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Tips on changing orifice size on AC or heatpump


Tips on changing orifice size on air conditioners and heat pumps.
A smaller orifice will create these changes
1 - Takes more refrigerant charge to get the same superheat
2 - Increases capacity
3 - Decreases Energy Efficiency Ratio
4 - Increases Head pressure
5 - Increases sub cooling
6 - Reduces suction pressure
7 - Increases Watts and Amps
A Larger orifice will create these changes
1 - Takes less refrigerant charge to get the same superheat
2 - Decreases Capacity
3 - Increases Energy Efficiency Ratio
4 - Decreases head pressure
5 - Decrease Sub cooling
6 - Increases suction pressure
7 - Reduces Watts and Amps

on Jan 26, 2010 | Air Conditioners

1 Answer

How i calculate 2ton window ac gas filling in kg


Please check the manual in which the total kg to be charged mentioned there.
The list and calculation differs to gas to gas and also depends on temp and PSI. Thanks.

Feb 04, 2011 | Air Conditioners

1 Answer

WHAT DOES 12000BTUh MEAN OR REPRESENT IN AIRCONDIONING terMS? eg 12000 or 10000


Hi,
I found this explanation which I certainly couldn't improve on.

The British thermal unit (BTU or Btu) is a traditional unit of energy. It is approximately the amount of energy needed to heat one pound of water one degree Fahrenheit. One Btu is equal to about 1.06 kilojoules. It is used in the power, steam generation, heating and air conditioning industries. In scientific contexts the BTU has largely been replaced by the SI unit of energy, the joule (J), though it may be used as a measure of agricultural energy production (BTU/kg). It is still used 'unofficially' in metric English-speaking countries (such as Canada, the United Kingdom), and remains the standard unit of classification for air conditioning units manufactured and sold in many non-English-speaking metric countries.
In North America, the term "BTU" is used to describe the heat value (energy content) of fuels, and also to describe the power of heating and cooling systems, such as furnaces, stoves, barbecue grills, and air conditioners. When used as a unit of power, BTU 'per hour' (BTU/h) is understood, though this is often abbreviated to just "BTU".

I located it at this site all credit for this info is:
http://en.wikipedia.org/wiki/British_thermal_unit

Hope this is what you need,
RSMITH972278
P.S. PLEASE RATE ME !

Oct 18, 2009 | Air Conditioners

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Tax Incentives for Heating and Air Conditioning


The passage of the American Recovery and Reinvestment Act of 2009, consumers are able upgrade to more energy-efficient heating and air conditioning equipment. They can start saving on energy bills right away, and you may also save on your taxes next year. For your home, these benefits can include lowering home energy bills, increasing your indoor comfort, and reducing air pollution. These programs are helping savvy consumers’ lower energy bills in their home. The energy-efficient products that are eligible for the new federal tax credits can lower the amount of federal income taxes that many taxpayers must pay Uncle Sam.

There are some new potentially lucrative tax incentives for energy-efficient and renewable-energy home improvements. These may offer some consolation to many homeowners who feel they are getting forgotten with the government's various economic stimulus efforts.

There is a $1,500 energy-efficient credit, which currently will last only last two years, meaning consumers will have to find a way to spend this money during this economic downturn. Homeowners now have a new opportunity to lower their energy costs and save on their 2009 federal income taxes by making specific energy efficiency upgrades to their homes.

There is also a new tax credit that will be effective 2009 through 2016 for 30 percent of the cost of a qualified geothermal heat pump. This can be for up to $2,000. These caps do not apply to certain alternative energy systems like geothermal heat pumps, solar water heaters, wind power, or photovoltaic systems. The benefits for installing some pricier solar technology, small wind-energy systems or geothermal-well systems can include a tax credit of 30% for qualifying expenditures with no upper limit through 2016. In order for you to claim your credit, the energy efficient improvements you must use qualifying Energy Star rated products and they must be started up sometime between from January 1, 2009 through December 31, 2010.

By doing your research and talking with your heating and air conditioning professional you may be able to save a substantial amount of money and get some great home improvements at the same time.

on Dec 26, 2009 | Air Conditioners

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Air Conditioner SEER Seasonal Energy Efficiency Ratio


Energy consumption for home air conditioning accounts for almost 5% of all the electricity produced in the USA. Energy Policy Act mandates minimum energy efficiency standards for commercial buildings, using research and standards developed by the American Society of Heating, Refrigerating, and Air Conditioning Engineers. Energy Star qualified central air conditioners have a higher seasonal efficiency rating (SEER) than standard models, which makes them about 14% more efficient than standard models. Energy efficiency specialists with certified training on retrofits and energy savings on both residential and light commercial units may enable you to save up to 50 percent on your air conditioning bills with the use of a high efficiency energy system. Substantial energy savings can be obtained from more efficient systems.

SEER (Seasonal Energy Efficiency Ratio) is related to the Energy Efficiency Ratio (EER), which is the ratio of output cooling in Btu/Hr and the input power in watts W at a given operating point and also to the coefficient of performance (COP) commonly used in thermodynamics. SEER rating more accurately reflects overall system efficiency on a seasonal basis and EER reflects the system’s energy efficiency at peak day operations.

The SEER rating is the Btu of cooling output during a typical cooling-season divided by the total electric energy input in watt-hours during the same period. SEER is related to the Energy Efficiency Ratio (EER), which is the ratio of output cooling in Btu/Hr and the input power in watts W at a given operating point and also to the coefficient of performance (COP) commonly used in thermodynamics. SEER rating more accurately reflects overall system efficiency on a seasonal basis and EER reflects the system’s energy efficiency at peak day operations. The higher the SEER number, the greater the efficiency of your unit. Therefore you will realize greater energy savings. The higher efficiency your product, the lower your long-term energy costs will be. Both central AC and air source heat pumps are rated according to seasonal energy efficiency ratio (SEER).

Before you consider upgrading your cooling equipment, the cheapest way to save money and energy from cooling is to reduce the need for mechanical air conditioning in the first place. Ask your contractor about a variable speed air handler, which will improve comfort and efficiency and allow continuous air filtering at minimum energy cost. Also, because ducts are often responsible for a lot of wasted energy, make sure you hire a contractor who knows about high-efficiency installations. If your central air conditioning unit is more than 12 years old, replacing it with an Energy Star qualified model could cut your cooling costs by 30 percent.


on Dec 14, 2009 | Air Conditioners

1 Answer

I want to know how works


To understand this answer, you must first understand you cannot cool anything. Rather, you must remove its heat. You must accept that heat is energy and that energy cannot be destroyed. You must also understand that heat wants to go where it is cool.

An Air Conditioner "cools" by moving heat from one place to another using the ideas represented above..

An A/C compresses a gas into a liquid then sprays that liquid through a small hole where it returns to its former state, a gas. Then this happens, the gs is cold having given up its heat in the spraying process. The air passing over this cold gas (in a tube) passes the heat it contains to that cold pipe which absorbes it and moves it usually to the out of doors where a fan blowing relatively cooler over another set of coils and the heat passes from the hot coil to the cooler air.

From a physics stand point, you cannot destroy energy. In this case, heat is energy and we cannot destroy that energy. But, we can move it from place to place ... and when we move it to the out side, we dulute that energy into the atmosphere.

Oct 12, 2009 | Air Conditioners

1 Answer

How can we caculate the energy needed by an air conditioner?


It depends on the (EER) Energy Efficiency Ratio,which is capacity divided by watts.
Example 35000 btus / 2500 watts = 14 EER
If you know the capacity,btus and EER you can calculate the watts, capacity / EER
Example 35000 btus / 14 EER = 2500 watts.

EER is determine by testing the air conditioner at Department of Energy Guidelines, which are
80° drybulb 67° wetbulb indoor and 95° and 82° drybulb outdoor.

May 14, 2009 | LG LS-K2430HL Heat Cool Mini Split Air...

Tip

Air Conditioning Programmable Thermostats - Great for Heating and Cooling


Programmable thermostats contribute to overall system performance, maximizing energy savings while providing complete comfort control. They also allow flexibility to homeowners because they can be programmed to match their lifestyle. Programmable thermostats save energy by turning down the cooling and heating system at night or at times when your home is typically unoccupied.


Did you know that properly using a programmable thermostat in your home is one of the easiest ways you can save energy, money. Homeowners can save about $180 a year by properly setting their programmable thermostats and maintaining those settings. They can achieve significant energy and money savings that are possible through the proper use of your programmable thermostat. Programmable thermostats do two things:
(1) Compare the thermometer reading of a room's temperature to the "ideal" thermostat temperature you select.

(2) Give start-and-stop commands to the heating or cooling system in order to achieve an indoor temperature that is as close to your "ideal" thermostat setting as possible.


Your savings will largely depend on the length of your energy saving program periods and the temperatures set. For example, an energy saving period of 10 hours with the temperature set back 10° will save more than a 5 hour energy saving period with the temperature set back 5°. By maintaining the highest or lowest required temperatures for four or five hours a day instead of 24 hours, a programmable thermostat can pay for itself in energy saved within four years.

A programmable thermostat will keep you and your home comfortable while you are there to enjoy it, and will change the set point at programmed times to an energy savings level when you are not home. The precise temperature control of a programmable, energy-saving thermostat saves wear and tear on high-efficiency heating and cooling equipment by properly cycling the equipment. A programmable thermostat will keep you and your home comfortable while you are there to enjoy it, and will change the set point at programmed times to an energy savings level when you are not home.


Controlling your heating more effectively could save you up to 17% on your heating costs. In fact, during the winter you can save about 3 percent of your heating costs for every degree you lower your thermostat. Begin lowering your heating bill immediately with the pre-programmed 7-day schedule, or modify the programming to suit your lifestyle. By delivering the heating or cooling when you need it, and optimizing temperature for activity, sleep and times you are away you can maximize your comfort level and save energy.

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on Dec 06, 2009 | Air Conditioners

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