Comparative Study on the Thermal Performance of LEDs and Fluorescent Lamps

A study on the issues facing LED lighting in general illumination lighting has been published in "IEEE Transactions on Power Electronics - Vol. 24 No. 7". Authored by in part by Dr. Ron Hui - IEEE Distinguished Lecturer PELS. This study states that despite claims of high efficacy, LED output performance is only true at low junction temperatures and not sustainable at high temperatures (which is the normal operating environment for many general illumination lighting applications). The study refers to the need to identify the “hidden issues” associated with LED lighting. A surprising number in this study was that while linear fluorescent tubes dissipate between 73%-77% of total lamp power as heat - LEDs dissipate 87%-90% of input power as heat.

This supports what we have been hearing from the LED industry - that LEDs will only be a viable solution in general illumination lighting when consumers and businesses are willing to install new LED specific lighting fixtures.



This report can be acquired at:


http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?isnumber=5075737&arnumber=5175610&count=20&index=15


A Simple Method for Comparative Study on the Thermal Performance of LEDs and Fluorescent Lamps
Yaxiao Qin Deyan Lin Hui, S.Y.
Dept. of Electron. Eng., City Univ. (CityU) of Hong Kong, Kowloon, China;
This paper appears in: Power Electronics, IEEE Transactions on
Publication Date: July 2009
Volume: 24, Issue: 7
On page(s): 1811-1818
ISSN: 0885-8993
INSPEC Accession Number: 10812269
Digital Object Identifier: 10.1109/TPEL.2009.2017021
Current Version Published: 2009-07-28


Abstract


A simple method is proposed to measure the heat dissipation of LEDs and fluorescent lamps in an open system that allows light energy to escape. Based on this method, a comparative study on the thermal and luminous performance of high-brightness LEDs and fluorescent lamps is presented. At rated power, T5 and T8 fluorescent lamps generate about 73%-77% of their total power as heat, while three types of high-brightness LEDs dissipate about 87%-90% of input power as heat. Heat dissipation is an important factor particularly for air-conditioned buildings when overall energy efficiency is considered. T5 fluorescent lamps perform better than some existing LEDs in terms of luminous efficacy and heat generation in this study.

Proposed Product Specifications

We have had many requests regarding the proposed performance of the Vu1 ESL R-30 bulb.  The following specifications are those that we have established with Vu1’s engineering and manufacturing groups for our first product.  Some of these specifications have already been met.   Final published performance to these specification will come from independent lab testing, formal certification reporting and through product safety testing that will be conducted by groups such as UL and ETL.   These are the TARGET specifications that Vu1 is currently working toward.

Vu1 ESL R-30 Reflector Bulb

Product Description

Vu1's first consumer product will be a reflector bulb in the R-30 shape.  The R-30 is the predominant bulb utilized in recessed can lighting applications.    R lamps designed for use in places such as showroom floors, museums and for general overhead lighting in homes where a smooth distribution of light with a soft-edged beam is desired. 

Product Specification (proposed)

Functionality

The Vu1  R-30 will be a direct replacement for any R-30 incandescent reflector bulb.  In shape, size, and performance (illumination, light color, dimablity, instant on) the Vu1 ESL R-30 will be indistinguishable from an incandescent R-30.

Performance

Nominal Wattage		=<20 W
Lumens output		=>600 lm
Color Temperature (CCT)		2700-2850K
Color Rendering Index (CRI)		>90
Power Factor		>90
Rated Life		=> 6000 hours
Instant on		=< 250 ms  (at full power or any pre- dimmed level)
Fully dimmable		Constant dimability to 20%
Beam Angle		60 degrees
Glare		Minimal, similar to frosted incandescent R30
Voltage		120VAC

Form Factor / Compatibility

Shape		Compatible with all existing R30 fixtures
In fixture		Indistinguishable from incandescent R30
Lamp finish		White face
Maximum Overall Length		5.75 inches
Diameter		3.75 inches
Base		E26 screw base and GU24 pin base
Weight		=< 12 ounces
Heat tolerance		Designed for ventilated and non-ventilated recessed can fixtures
Wet environment		Indoor or dry environment only
Cold environment		Performance unaffected by temperature

Environmental and Safety

Materials		Non-toxic case, glass, electronics, phosphor
Emissions		No X-ray, No UV
Breakage risk		All materials contained by safety coating
EFI		Meets FCC regulations
Heat generation		>50% less than 65W incandescent R30

Vu1 Bulbs Burn Down Trailer Park :-)

In the category of "we couldn't make this stuff up" - we were just forwarded a post from an investor message board that claims Vu1 Bulbs are responsible for burning down a trailer park!! The folks around Vu1's HQ have had great fun passing this one around. We just sent it over to our team in the Czech Republic advising them that we obviously need to tighten up our safety testing. We will have to go back to our contacts at UL and make sure that when we start the certification process they will be specifically testing for trailer fixtures to make sure this never happens again!!

btw- we also have heard that our energy efficient, mercury free, Earth Saving Lights (ESL) may be responsible for Global Warming. Our apologies to the polar bears that called this in.

Vu1 in the News

Vu1 and ESL was mentioned into today's Huffington Post.


"There are a lot of guides out there to help you choose bulbs with the least amount of mercury and the most flattering light -- the Environmental Working Group's Green Lighting Guide is a helpful starting point. But I'll be honest: I'm really looking forward to when LEDs (light-emitting diodes), which are even more efficient than CFLs and arguably more flattering, start to come down in price. There's also been some buzz about the new ESL (electron stimulated luminescence) bulb from Seattle manufacturer Vu1 that is currently in development -- no mercury, 65 to 70 percent less energy than incandescents, and virtually indistinguishable from the real deal."



Read more at: http://www.huffingtonpost.com/jennifer-grayson/eco-etiquette-help-compac_b_303908.html