Re: Heat Calculation
Hi Lauren: At the risk of being shown otherwise... Determining the actual heat dissipation of your product could be very time consuming. It would involve, in part, knowing the electrical efficiency of I would argue that, using the law of conservation of energy, this is not at all time consuming, and is really quite easy. The product takes in electrical energy. All of this energy must be accounted for in terms of dissipation of that energy -- in some form other than electrical energy. Most of the components are energy transducers -- they change the electrical energy into some other form of energy. Resistors, semiconductors, inductors, transformers, and some capacitors all dissipate electrical energy in the form of thermal energy. LEDs and CRTs dissipate electrical energy into both thermal energy and light energy. Motors transform electrical energy into both thermal energy and kinetic energy. (The kinetic energy is then dissipated in friction which converts the kinetic energy to thermal energy.) Charging a battery converts electrical energy to thermal energy and chemical energy. The vast majority of the electrical energy is dissipated as thermal energy. Best regards, Rich - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Heat Calculation
Determining the actual heat dissipation of your product could be very time consuming. It would involve, in part, knowing the electrical efficiency of all components used. Because all components deviate from their ideal models, some of the electrical energy that passes through them is converted to heat. But for each component, it is a different amount of 'waste.' You could go through a rough analytical guess of determining the largest power consuming components and make a stab at their efficiencies and add them up. You could go through a rough empirical test measuring temperature rise of ambient air around your equipment in a controlled chamber. Often this number is used by your customers so they can calculate how much cooling they need to maintain your recommended ambient temperature conditions. In this case the number can be whatever 'the market will bear'. That is, it sort of acts as the statement We promise our equipment won't load your cooling system at a rate greater than X Btu/hour In this case it does matter what your equipment actually does as long as it is not perceived to exceed that limit. In this light it is likely that someone at your company made an educated empirical or analytical guess at the maximum foreseeable heat dissipation of one product and realized it would not significantly change (significant in the eyes of your market) from product to product, and hence the same number is always used. It is a number your customers can use to model cost of ownership of your product. -Lauren Crane Eaton Corporation -Original Message- From: s_doug...@ecrm.com [SMTP:s_doug...@ecrm.com] Sent: Tuesday, April 27, 1999 10:47 AM To: emc-p...@majordomo.ieee.org Subject: Heat Calculation Hello, Does anyone know how to compute heat dissipation for a product given mains power input (volts, amps, watts)? Our spec sheets always list heat dissipation (e.g. 1,000 BTU/hour) for each product and I wonder where the number comes from and why it never changes from one product to the next. Thanks for any comments received. Scott s_doug...@ecrm.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Heat Calculation
Scott: Heat output from electronic products can be calculated using the formula: btu / hour = Watts * 0.29307 Also, you can check out the following website for other useful conversion factors: http://www.megaconverter.com/Cv_start.htm Best regards, Ken Shadoff Senior Product Safety Engineer Quality Management Dept. Canon U.S.A., Inc. kshad...@cusa.canon.com Tel: 516-328-5602 Fax: 516-328-5169 From: s_doug...@ecrm.com (Scott Douglas) AT ~internet on 04/27/99 10:47 AM To: emc-p...@majordomo.ieee.org AT ~internet@FCC cc:(bcc: Kenneth A. Shadoff/NewYork/CanonUSA) Subject: Heat Calculation Hello, Does anyone know how to compute heat dissipation for a product given mains power input (volts, amps, watts)? Our spec sheets always list heat dissipation (e.g. 1,000 BTU/hour) for each product and I wonder where the number comes from and why it never changes from one product to the next. Thanks for any comments received. Scott s_doug...@ecrm.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Heat Calculation
http://www.ios.doi.gov/pam/eneratt2.htm Give the above link a try. 3412 BTU = 1 kWh 1 watt = 3.412 BTU/Hr 293 watts = 1000 BTU/Hr. Watts dissipated = watts inDon't confuse volt amps with watts. Jim Allan Senior Compliance Engineer Milgo Solutions Inc. E-mail james_al...@milgo.com -Original Message- From: s_doug...@ecrm.com [SMTP:s_doug...@ecrm.com] Sent: Tuesday, April 27, 1999 10:47 AM To: emc-p...@majordomo.ieee.org Subject: Heat Calculation Hello, Does anyone know how to compute heat dissipation for a product given mains power input (volts, amps, watts)? Our spec sheets always list heat dissipation (e.g. 1,000 BTU/hour) for each product and I wonder where the number comes from and why it never changes from one product to the next. Thanks for any comments received. Scott s_doug...@ecrm.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Heat Calculation
Scott, 1W/hr = 3.413BTU/hr 1Kw/hr = 3,413 BTU/hr John A. Juhasz Product Qualification Compliance Engr. Fiber Options, Inc. 80 Orville Dr. Suite 102 Bohemia, NY 11716 USA Tel: 516-567-8320 ext. 324 Fax: 516-567-8322 -Original Message- From: s_doug...@ecrm.com [mailto:s_doug...@ecrm.com] Sent: Tuesday, April 27, 1999 10:47 AM To: emc-p...@majordomo.ieee.org Subject: Heat Calculation Hello, Does anyone know how to compute heat dissipation for a product given mains power input (volts, amps, watts)? Our spec sheets always list heat dissipation (e.g. 1,000 BTU/hour) for each product and I wonder where the number comes from and why it never changes from one product to the next. Thanks for any comments received. Scott s_doug...@ecrm.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Heat Calculation
Hi Scott: Under the law of the conservation of energy, all of the energy going into a product must be accounted for. Energy is measured in joules. One joule is one watt-second. One watt is one joule/second. All of the watts entering the product must be accounted for. All of the watts are converted to some other form of energy. If the product has moving parts, some of the electrical energy is converted to kinetic energy. (The kinetic energy is ultimately converted to thermal energy in the friction of the mechanical system.) If the product has light output (i.e., LEDs, CRT), some of the electrical energy is converted to light energy. (This conversion is very inefficient; very little energy is converted to light energy.) If the product has semiconductors and resistors and similar devices, some of the electrical energy is converted to thermal energy in those devices. So, for all practical purposes, all of the electrical energy is converted to thermal energy. One watt is 3.41443 BTU/hour. So, for all practical purposes, the product dissipates 3.41443 BTU/hour/watt. If your product is disspating 1000 BTU/hour, then its input must be 1000/3.41433 or 293 watts The BTU/hour is a function of the input power (watts). If the input power changes from product to product, then the BTU/hour must likewise change from product to product. Best regards, Rich - Richard Nute Product Safety Engineer Hewlett-Packard Company Product Regulations Group AiO Division Tel : +1 619 655 3329 Effective 6/12/99: +1 858 655 3329 16399 West Bernardo Drive FAX : +1 619 655 4979 Effective 6/12/99: +1 858 655 4979 San Diego, California 92127 e-mail: ri...@sdd.hp.com - - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Heat Calculation
Scott, One British thermal unit (Btu) is the quantity of heat or thermal energy required to raise the temperature of one pound of pure water one degree F. The unit for thermal energy is the joule (J). One kilojoule = 0.9478 Btu. The watt (W), equal to joule per second (J/s), is used for power, where one watt = 3.412 Btu per hour. Regards, Kevin J. Hight -- Regulatory Compliance Engineer Exabyte Corporation 1777 Exposition Drive, Building #7 Boulder, Colorado 80301 Phone: 303-417-5534; Fax: 303-417-5710 Pager: 303-855-7029; Email: kev...@exabyte.com -Original Message- From: s_doug...@ecrm.com [mailto:s_doug...@ecrm.com] Sent: Tuesday, April 27, 1999 8:47 AM To: emc-p...@majordomo.ieee.org Subject: Heat Calculation Hello, Does anyone know how to compute heat dissipation for a product given mains power input (volts, amps, watts)? Our spec sheets always list heat dissipation (e.g. 1,000 BTU/hour) for each product and I wonder where the number comes from and why it never changes from one product to the next. Thanks for any comments received. Scott s_doug...@ecrm.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Heat Calculation
Multiply watts by 3.415 to obtain BTU/hour. To compute the input power you need to multiply the rms voltage, rms current and power factor. Or you can cheat and use a wattmeter. -- From: s_doug...@ecrm.com [SMTP:s_doug...@ecrm.com] Sent: Tuesday, April 27, 1999 10:47 AM To: emc-p...@majordomo.ieee.org Subject: Heat Calculation Hello, Does anyone know how to compute heat dissipation for a product given mains power input (volts, amps, watts)? Our spec sheets always list heat dissipation (e.g. 1,000 BTU/hour) for each product and I wonder where the number comes from and why it never changes from one product to the next. Thanks for any comments received. Scott s_doug...@ecrm.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Heat Calculation
According to a table of Conversion Factors that I found on page 18 of the December 1991 Electrical Manufacturing magazine, and keep stashed in my dictionary here at work: Watts * 3.413 = BTU's/hour I use the maximum input power (wattage) that we have measured for a product in its various operating modes, after it has been turned on and warmed up for a while. Every time that I have been asked the question it is in the context of calculating the air-conditioning requirements for a customer site. John Barnes Advisory Engineer Lexmark International s_douglas%ecrm@interlock.lexmark.com on 04/27/99 10:47:28 AM Please respond to s_douglas%ecrm@interlock.lexmark.com To: emc-pstc%majordomo.ieee@interlock.lexmark.com cc:(bcc: John Barnes/Lex/Lexmark) Subject: Heat Calculation Hello, Does anyone know how to compute heat dissipation for a product given mains power input (volts, amps, watts)? Our spec sheets always list heat dissipation (e.g. 1,000 BTU/hour) for each product and I wonder where the number comes from and why it never changes from one product to the next. Thanks for any comments received. Scott s_doug...@ecrm.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Heat Calculation
Hello, Does anyone know how to compute heat dissipation for a product given mains power input (volts, amps, watts)? Our spec sheets always list heat dissipation (e.g. 1,000 BTU/hour) for each product and I wonder where the number comes from and why it never changes from one product to the next. Thanks for any comments received. Scott s_doug...@ecrm.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
