What is Heater: Definition and 202 Discussions

Heating, ventilation, and air conditioning (HVAC) is the technology of indoor and vehicular environmental comfort. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics and heat transfer. "Refrigeration" is sometimes added to the field's abbreviation, as HVAC&R or HVACR or "ventilation" is dropped, as in HACR (as in the designation of HACR-rated circuit breakers).
HVAC is an important part of residential structures such as single family homes, apartment buildings, hotels and senior living facilities, medium to large industrial and office buildings such as skyscrapers and hospitals, vehicles such as cars, trains, airplanes, ships and submarines, and in marine environments, where safe and healthy building conditions are regulated with respect to temperature and humidity, using fresh air from outdoors.
Ventilating or ventilation (the "V" in HVAC) is the process of exchanging or replacing air in any space to provide high indoor air quality which involves temperature control, oxygen replenishment, and removal of moisture, odors, smoke, heat, dust, airborne bacteria, carbon dioxide, and other gases. Ventilation removes unpleasant smells and excessive moisture, introduces outside air, keeps interior building air circulating, and prevents stagnation of the interior air.
Ventilation often refers to the intentional delivery of the outside air to the building indoor environment. It is one of the most important factors for maintaining acceptable indoor air quality in buildings. Methods for ventilating a building are divided into mechanical/forced and natural types.

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  1. Q

    Heat Car Engine on Cold Morning: Tips & Advice

    Does anyone know the proper way to do this?
  2. E

    Fluid and heat transfer in a hot water heater

    Please help me with this : 1) Water circulates throughout a house in a hotwater heating system. The water is pumped at a speed of .7 m/s through a 4 cm diameter pipe in the basement under a pressure of 3 atm. What is the pressure, to the nearest N/m^2, in a 2 cm pipe on the second floor 5...
  3. A

    Understanding the Purpose and Placement of a Feed Water Heater's Drain Cooler

    1. What is the function of drain cooler in a feed water heater and is there any reason that it is integral within the heat exchanger but some times it is also placed outside the heater. Homework Equations 3. ok i got to know the function of a drain cooler.it sub cools the...
  4. A

    Understanding the Function and Placement of Drain Coolers in Feed Water Heaters

    What is the function of drain cooler in a feed water heater and is there any reason that it is integral within the heat exchanger but some times it is also placed outside the heater.
  5. O

    Connecting a 240v Water Heater to a Timer/Switch

    Hello, I have a 240v water heater with a machincal timer which went bye-bye after I installed it over 15 years ageo. Those darn plastic gears finnaly broke. So I bought a Intermatic EH40. The line is 240v with 3 wires (white, black, and ground) which matches the water heater wires...
  6. T

    Fanless convection heater versus oil filled heater

    Both are near silent and 100% (in)efficient, but does the convection heater (with the electric coil where heat rises naturally) make the room more stuffy as I've sometimes heard, or perhaps even deplete oxygen?
  7. JaredJames

    Why Is My 2kW Fan Heater Only Using 0.7kW?

    Hi, I have a fan heater which is rated at 2kW but when we check what it is actually using (voltage x current) it is only using 0.7kW. I am curious as to why this is? This is the fan: http://www.amazon.com/dp/B000306BL4/?tag=pfamazon01-20 Are these fans 100% efficient? Thanks...
  8. J

    How did my water heater cause a flood in my apartment?

    2 years, 2 different kinds of water heaters, 2 flooded apartments. Last time I was fortunate enough that all the leakage went out the door, but when it happened two days ago it flooded my bedroom and closet during the night. Yeah, that was fun...I step out of bed onto the carpet...
  9. C

    Find a SiC Heater for PLD System

    help me find it out:) hi guyz, i'd like to know where i can buy the SiC heater of the PLD(pulsed laser depositon) system. the one of our lab is broken...in addition, i have some questions about p-type ZnO, i hope someone would help me :) thanx!
  10. T

    Optimizing Solar Water Heater Efficiency for Pool Heating

    I thought Wolfram Alpha might be able to help me with this problem, however so far I have had no luck, with the website nor their community: I have a 1230 gal pool heated by the sun to 70 degrees F, If I remove 30 gal and let the 30 gal be heated in my solar collector to 100 degree F, and...
  11. N

    Can a Small Motor Effectively Heat Nichrome Wire for a Low Power Heater?

    Ok, I'm rather new to electronics as I've only taken a high school-level electronics class and that was several years ago. Right now I'm trying to put together a low power heater consisting of a length of nickel chromium wire and a DC or stepper motor. What I'd like to do eventually is be able...
  12. T

    Using a Variac to heat a flexible rope heater

    Hi, I want to use a variac that I've got (4A rating) to power one of these: http://www.omega.co.uk/ppt/pptsc.asp?ref=FGS_FGH_FWH&Nav=heam02 but a 240V version. The problem is I can't figure out if the variac that I've got has sufficient grunt to do it (without frying me, the variac or...
  13. S

    Solving the Resistance of an Electric Water Heater

    Homework Statement A well-insulated electric water heater warms 137 kg of water from 20°C to 45.0°C in 16.0 min. Find the resistance of its heating element, which is connected across 220-V potential difference. Homework Equations R=V/I The Attempt at a Solution Not sure how to...
  14. F

    Water heater and area of sunray gatherer

    Homework Statement A water heater gathers energy with the help of solar collectors on the roof, where water circulates in pipes and are provided heat from the sunrays that get through a transparent cover. The water is then pumped down in a tank inside the house. What area must the...
  15. I

    How This Heater get ON and OFF

    1.If i apply voltage 440volts at L1,L2,L3 the K3 (contactor) will get on automatically? 2.How this SSR work and what should be the voltage at 4,5,6 and 7,8,9(X1 terminals)? The main thing i want to ask is how this heating 1 and heating 2 gets ON and OFF and at what voltage? Thank you.
  16. G

    Making a non pressurized water heater

    I want to make a water heater from an insulated 50 gallon bucket, but I could easily use a different size container. I tried doing things the easy way by just looking for an immersion heater than can be plugged straight into an outlet, but all I can find are travel heaters for making coffee...
  17. Z

    Building a water heater- using battery and wire

    Homework Statement Need to heat 30mL of water from 20C to 40C in 1 min(60s). Using 6V battery and Nickel Chromium alloy Nichrome wire that has a resistivityabout 10^-6 ohms/meter. So you use the battery and the wire to build a water heater. Batter has no internal resistance. Homework...
  18. D

    Is It More Efficient to Leave the Heater On or Turn it Off?

    Is it better to leave the heater going constantly or turn it off when you leave the house? I've heard people tell me that it takes more energy to bring it back up to temperature every day than it does to just leave it running all day. That doesn't seem intuitive to me.. is it true?
  19. G

    Solving a 1500 W Heater Short Circuit

    The problem is that a space heater develops a short circuit when to much current enters the circuit. The power supplied is 1500 W and the max current before short circuit is 15A. Firstly we have to calculate the resistance of the heater where I used P = I^2 R. But now we have to find the...
  20. G

    Designing a Solar Water Heater System for 4500 Gal Tank

    The problem is designing a solar water heater system to keep a 4500 gal tank of water at 140F during the day. The tank in question has the following properties: 5000gal Volume 4500gal water It loses about 1.8 degrees F/hr if not heated. I first need to figure out amount of energy...
  21. J

    Oil Heater, Humididy, Heating Cold Air

    Hi I am living in a 2 bedroom house with base bord heaters but i have also purchesed 3 oil space heaters, my landlord since has givin me a bogus eviction notice because of to much humididiy in the air, his fault really for nothin ensuring propor ventalation when repairing the house but my...
  22. D

    Clothes Iron versus baseboard heater

    Hi, My friend and I were having a discussion and had a disagreement. I'm hoping one of you intelligent people can settle it for us. There are two points I'd like to talk about. 1. Safety concerns and practicalities aside why would one choose to heat a room with a baseboard heater versus an...
  23. M

    Home Made Pool Heater: Calculate Heating Time & Coal Use

    >>>>>>>Home made pool heater.<<<<<<<<< Ok, i know this sound a little stupid. I would like to make a home made hot tub for my mates for this Xmas. I have put together a manifold from 15mm Dia copper tubing and is 8 Meters long. I will be heating this manifold within a beer keg that...
  24. N

    How a Cathode Heater Works: A Clear Explanation

    How does a cathode heater work? Can't seem to find a straightforward explanation anywhere.
  25. J

    Is a Battery/Solar Powered Heater Feasible and Safe for Personal Use?

    Hey, I have an idea for a device that I'm trying to fabricate, and I could use some help with the design. Hopefully you can tell me if what I want to do is possible, and what components I'd need. Thanks. My idea is for a device, maybe 6 inches long by four wide that would contain a damp...
  26. A

    Determine curren in a 1500 W water heater connected to 220 V

    A 1500 W heater is connected to 220 V. Calculate a) the current in the heater b) the resistance of the heater c) the termal energy provided by the heater in 1 hour
  27. B

    Understanding Closed Feedwater Heaters and Regeneration in the Rankine Cycle

    I have a question on the rankine cycle with a closed feedwater heater. My thermo book says that in an ideal closed feedwater heater, the feedwater is heated to the exit temperature of the extracted steam. I don't really understand this. I know the bleed steam from the turbine is cooled to a...
  28. R

    Little project - rechargeable pocket heater?

    I work outside, and have absolutely no circulation in my hands. And I like hair-brained schemes. So with these things in mind, I thought I might have a crack at making a little rechargeable pocket heater. Unfortunately, I know very very little about actual electrics. But hey, that's what...
  29. U

    Anyone thought of combining solar water heater with Stirling generator?

    I've heard that solar water heating is very efficient, almost all the radiation of the sun on the panel is turned into heat. Also heard Stirling cycle generators (where heat flow from hot to cold is turned into mechanical motion and hence into electricity) are also quite efficient. Though by...
  30. T

    Should I leave my heater on 24/7 ?

    I've got an electric heater in my appartment. It's on a timer that turns it on at 1200 and off at 2300. While on it's controlled by a thermostat. My question is this; is it more economical for me to leave it on 24/7 instead of what I'm currently doing, the theory being that whatever I save...
  31. D

    Dimmer or router speed control as resistance heater level control

    I'm trying to figure out how to safely use a dimmer or router speed controller as an inexpensive heat level control for a (nichrome coil) resistance heater. I've read that you can use a dimmer switch as a heat control if you don't run it at more than 80 percent of its watt rating...
  32. Chi Meson

    Realizing Savings with Solar Hot Water Heater - My Experience

    For those interested, I have just received my third electricity bill after the installation of my solar hot water heater. Currently, I have realized at total of $158 "saved." Putting that against ~$3500 of total cost, then somewhere between $1200 and $2000 federal tax credit , and the...
  33. K

    Thermal Conductivity of an Infinite Thin Plate with a heater on it

    Homework Statement It's not a homework problem, but an engineering problem I try to solve before I delve into experimentation :smile: I have a source of heat (SSR - a solid state relay) that's well thermally coupled to the inside of a steel box. The thermal resistance between the SSR and the...
  34. O

    How do I calculate BTU? (for a water heater project)

    The last time I dealt with any physics was 6 years ago in college, so forgive my apparent ignorance: The Situation. I have a swimming pool pump outside near the house's air conditioner unit (heat exchanger I think it's called). Well, the freon is coming out of the house in copper pipes to...
  35. N

    Help me design my carputer to work in the cold (advice on building a heater)

    Help me design my "carputer" to work in the cold (advice on building a heater) Hello. You guys seem to be a knowledgeable bunch, so I thought maybe I'll post thing. My problem is that I custom built a computer to run in my car and I really need some help. I live in Calgary, Canada where in...
  36. F

    Solar powered heater for greenhouse

    I'm new to the site, and to solar power fundamentals. I'm interested in building a small greenhouse with as little impact on the environment as possible. I'd like to develop a solar system to maintain an even temperature. Unfortunately I live in Wisconsin. Any help in design issues would be...
  37. E

    Solar Water Heater Installation Cost: $/Watt

    Just curious...how much would it cost you to install a solar water heating system ($/Watt) where u live?
  38. E

    Pool Heater Installation and Comparison Questions

    anyone who has a pool heater? or knows how they are installed? if yes...please let me know what is the power rating of the pool heater and what size the pool is..i need it for comparison issues. (power in BTU/Hr, kW, J/s...) thnx Elie
  39. W

    Electrical heater using resistors

    Hi people is my first time posting in this forum... Great Forum¡¡¡ Every Sunday I work selling breakfast food and I got the same problem of all. Food getting cold, so I want to build a heater to maintain the food warn, just to keep it warn for the people be satified of my business...
  40. Q

    Law of Conservation of Energy of a water heater

    Imagine that your water heater has broken, but you want to take a bath. You fill your bathtub with 25 kg of room-temperature water (about 25 C). You figure that you can boil water on the stove and pour it into the bath to raise the temperature. How much boiling water would you need in order to...
  41. B

    Heater causes room temp to rise

    Here's yet another problem causing me trouble. I just don't understand(yet again) how to begin the problem. A little nudge in the right direction would be very much appreciated! If a heater supplies 1.8 x 10^6 J/h to a room 6.5m X 4.6m X 3.0m containing air at 20 deg C and 1atm, by how much...
  42. E

    What is the resistance of the heater?

    "A student uses an immersion heater to heat a cup of water (300mL) from 20ºC to 80ºC for tea. If it is 75% efficient and takes 2.5 min, what is the resistance of the heater? (Assume 120-V household voltage.)" Here's what I did: V= 0.75 * 120 = 90V mass of water = 0.3 kg, specific heat c =...
  43. S

    Battery and Solar powered heater

    Hi, I'm a business student working on a business concept, and I need some help with an electrical problem. I am attempting to design a product that stays warm, 50 degrees when the temperature outside is 0 or more. This is insulated, have a volume of around 1200 inches, and is powered by the...
  44. P

    Calculating Time for Immersion Heater to Raise Water Temperature

    Extracted from another thread tha had got a bit messy. The immersion heater in an electric hot water system is rated at 9 kW. If the tank is initially filled with 40 gallons (about 150 litres, with a mass of 150 kg) of cold water at 15 oC, how long will it take the heater to raise the...
  45. Mk

    Power saving with the water heater

    Will turning the water heater on and off save pwoer!>!>?!?
  46. M

    Can You Electrocute Yourself With Water Heater?

    we have heard of fatal electrocution from direct contact with "leaky" water heater. but can one get electrocuted without actually touching the short-circuited water heater parts? i mean, the shower head was on the wall and the person taking shower was sort of busy scrubbing himself. can...
  47. T

    Extension cord connected to heater - Find the power

    An extension cord made of two wires of diameter 0.129 cm (no. 16 copper wire) and of length 2.7 m is connected to an electric heater which draws 15.0 A on a 120V line. How much power is dissipated in the cord? Do I just use P=IV? But that leaves a lot of "extraneous" information. My...
  48. L

    Electrical Can DIY Resistors Create an Effective Portable Heater?

    DIY heater with resistors??! help please Hi physics gurus, I have some questions I'm hoping someone with a kind enough heart can answer for me! I am trying to build a small circular heater (similar to a dew heater for a telescope) with resistors. Basically I have 22 gauge rated 300volts...
  49. J

    What are the advantages of using an immersion heater at the top of a water tank?

    What are the advantages of using an immersion heater at the top of a water tank?
  50. Q

    Calculating Thermal Energy Supplied by Heater in 30.0s - Kilo-joules

    A heater has a resistance of 15.0 W. It operates on 120.0 V. What thermal energy is supplied by the heater in 30.0 seconds? Answer must be in Kilo-joules. Well o_o ..it would be nice if you could try to help me with this question. Since I recently moved from Germany to the U.S. with my...
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