Electric radiator tests

Transcription

1 Electric radiator tests Carried out for Haverland By P Stonard 16 July 2010

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3 Electric radiator tests Carried out for: Haverland Avda San Martin De Valdeigiesias Km-2,200 Alcorcon MADRID Spain Contract: Final Report 54180/1 Date: 16 July 2010 Issued by: BSRIA Limited Old Bracknell Lane West, Bracknell, Berkshire RG12 7AH UK Telephone: +44 (0) Fax: +44 (0) E: W: This report must not be reproduced except in full without the written approval of an executive director of BSRIA. It is only intended to be used within the context described in the text. BSRIA Page 3 of 32 Final Report 54180/1

4 CONTENTS CONTENTS 1 INTRODUCTION OBJECTIVE ITEM SUPPLIED FOR TEST SCOPE OF WORK AND TEST METHOD RESULTS ROOM TEMPERATURE RISE TIME WARMING UP TIME OF RADIATOR STABILITY OF ROOM TEMPERATURE EFFECT OF RADIANT HEAT VOLTAGE VARIATIONS...9 APPENDICES APPENDIX: A TEMPERATURE AND POWER RESPONSE TRACES APPENDIX: B THERMAL IMAGES OF RADIATOR DURING TEST TO DETERMINE WARM UP TIME APPENDIX: C RADIANT TEST APPENDIX: D TEST METHOD FREE STANDING ELECTRIC HEATERS VERSION 6 NOVEMBER FIGURES Figure 1 General view of installed radiator... 5 BSRIA Page 4 of 32 Final Report 54180/1

5 INTRODUCTION 1 INTRODUCTION This report details tests carried out on a Haverland electric radiator, model RC 12 TT. The tests were requested by Haverland and were conducted during the period 7 June to 9 July OBJECTIVE The objectives were to determine the radiator performance when subjected to a variety of tests, as follows: 1. Determine room temperature rise time against cooling load of two thirds of radiator output (radiator starts cold) 2. Determine warm up time of radiator to achieve 90% of its max surface temperature 3. Determine stability of temperature control when subjected to nominal cooling loads of 80%, 50% and 20% (or high, medium and low cooling ratio) 4. Determine radiant heat effect with two third cooling load applied. 2.1 ITEM SUPPLIED FOR TEST The item supplied consisted of a Haverland electric radiator, model RC 12 TT, with a nominal stated output of 1500 W at 230 V. It was a 12 section cast aluminium radiator with an integral programmable electronic thermostat, adjustable in increments of 0.5 C. Figure 1 General view of installed radiator BSRIA Page 5 of 32 Final Report 54180/1

6 SCOPE OF WORK AND TEST METHOD 3 SCOPE OF WORK AND TEST METHOD The methodology used was as the BSRIA test method for electrical and non-standard radiators. This incorporated principles and methods from BS EN 60675:1995 Household electric direct acting room heaters. Methods for measuring performance The BSRIA method document is included as Appendix C of this report and includes descriptions and diagrams of the test chamber and position of temperature probes. Clauses referred to below are those within the BSRIA method document. Tests were conducted as detailed in clauses Room temperature rise time (heating room from 15 C to 25 C with 66% cooling ratio), 2.2 Warming up time of radiator (from 18 C room temperature to 90% of maximum radiator temperature with 66% cooling ratio), 2.3 Stability of room temperature (at 20 C room temperature and various cooling ratio) and 2.4 Effect of radiant heat. Prior to tests commencing, a calibration of the chilled ceiling characteristic was conducted to determine the control temperatures required for various applied heating loads. At the same time data was collected to verify that the balance between heating and cooling load was within 5% under steady state conditions, using non-modulating resistance heaters controlled by means of a variac. In addition to the temperature probes stated within clause 2.1 of the BSRIA method, ten resistance thermometers were attached to and around the radiator, as shown in Figure 1. An infra red camera was also used during the warm up and radiant tests to observe the radiator. Images were taken using a 100 mm access port in the wall opposite the radiator at a distance of 4 m. The radiator was supplied at UK National grid voltage, which while being at nominal 230 V was actually 241 V during tests, giving a slightly higher output than the manufacturers stated nominal value. On completion of the tests a variable resistor was fitted to the power input and a series of tests conducted to determine the effect of voltage variations on radiator output. 4 INSTRUMENTATION The instrumentation used for tests consisted of: Description Identifier Yokogawa WT110 power meter 116 Agilent HP34970A data logger MY off 4 wire platinum resistance thermometers NSN 12off Type T thermocouples NSN Siemens Magflo 6000 waterflow meter 955 FLIR B50 Thermal imaging camera All instrumentation was ported to an automatic logging system, displaying on real time Excel spreadsheet, updated at 1 minute intervals. BSRIA Page 6 of 32 Final Report 54180/1

7 RESULTS 5 RESULTS Results for room temperature rise, warming up time of radiator and stability of room temperature are shown in graphical form with tabulated summary data below. Thermal images were also taken during the warm up time tests at 2 minute intervals Tests for the effect of radiant heat are shown as a combination of summary data and thermal images. 5.1 ROOM TEMPERATURE RISE TIME Conditions achieved during the room temperature rise tests were as detailed below. While the radiator thermostat was set at 25.0 C and the room started at 15 C. The radiator started to modulate the output before the control temperature was reached in the centre of the room. The room temperature increased by approximately 1 C after modulation occurred and before a steady state was reached. The reference temperature was taken from a probe at 1.5 m within a black globe at the centre of the room. Other temperatures plotted during this test and shown on the graphs for room temperature rise in Appendix A were at 0.5, 1.0, 2.0 and 2.2 m from the floor in the centre of the room. Parameter Test 1 Test 2 Test 3 Mean Mean cooling load Watts at steady state (modulating) Actual cooling ratio 1 67% 63% 64% 65% Time taken before radiator modulated output 58 minutes 61 minutes 59 minutes 59minutes Time taken before air temperature stability was achieved 166 minutes 160 minutes 166 minutes Globe temperature at steady state conditions ( o C) Radiator set point ( o C) minutes 5.2 WARMING UP TIME OF RADIATOR Conditions achieved during the radiator warm up tests were as detailed below. The radiator was at maximum set point and started from a room temperature of 18 C. The reference temperature was taken from a probe at 1.5m within a black globe at the centre of the room. Other temperatures plotted during this test and shown on the graphs for warm up time in Appendix A were at 0.5, 1.0, 2.0 and 2.2 m from the floor in the centre of the room. Additionally, thermal images of a warm up test were also taken and shown in Appendix B. Parameter Test 1 Test 2 Test 3 Mean Radiator output during test period (Watts) Maximum temperature reached (within radiator air column) ( o C) Maximum external surface temperature (front of radiator) ( o C) Time taken to reach 90% of maximum temperature (approximate warming up time) ( o C) 25 minutes 21 minutes 20 minutes Radiator set point ( o C) minutes This product is defined as a panel heater within BSEN in which the temperature rise of all surfaces in contact with the circulating air does not exceed 75 C in normal use 5.3 STABILITY OF ROOM TEMPERATURE The stability of the room temperature was determined from a 2 hour steady state period. Mean heat output was determined by a rolling integrated average power consumption (kwh) over the test period. BSRIA Page 7 of 32 Final Report 54180/1

8 RESULTS The mathematical standard deviation (STDev) is included for the temperature. Parameter Test1 STDev Test2 STDev Test3 STDev Actual cooling ratio 1 68% 53% 32% Mean heat output over 2 hr period (Watt) from integrated kwh Mean room temperature 0.5m ( o C) Mean room temperature 1.0m ( o C) Mean Globe temperature 1.5m ( o C) Mean room temperature 2.0m ( o C) Mean room temperature 2.2m ( o C) Radiator set point 2 ( o C) Note: 1. as a proportion of the maximum measured output during warm up of 1620W 2. Set point adjusted to give nominal 20 o C Globe at largest cooling ratio. From the above tests two parameters are calculated: Drift: The difference between the average room temperature obtained at different energy ratios for a constant setting of the ambient temperature thermostat Amplitude: The difference between the maximum and minimum room temperatures for a setting of the ambient temperature thermostat. Drift, is calculated from the high and low energy ratio tests: 60 D = ( t B t A )* A B D=drift t A = average room globe temperature at high energy ratio t B = average room globe temperature at low energy ratio A= measured value of high energy ratio B= measured value of low energy ratio 60 = difference between standard high and low energy ratio D=( ) * 60/39 = 2.6 C Amplitude is determined from the maximum and minimum globe temperatures over the two hour steady state period at 50% energy ratio. Amplitude = 0.2 C For additional information, amplitude at the high energy ratio was 0.4 C and for the low energy ratio 0.1 C, determined from the globe temperature. BSRIA Page 8 of 32 Final Report 54180/1

9 RESULTS 5.4 EFFECT OF RADIANT HEAT Assessments were made of the temperature rise of a black painted board 1.5 m x 1.0 m placed 1 m in front of the radiator, compared against a shielded probe 0.2 m behind it, at 0.5 m height.. Temperature rises were small (less than 3 degrees), while the temperature rise distribution on the face subjected to radiant heat was approximately 2 degrees. Lowest temperature rise was zero at the base of the board rising to 2.1 at the top. This indicates the radiant heat is a small component of the overall radiator output. Thermal images in Appendix B show front and rear views of the test board. 5.5 VOLTAGE VARIATIONS The test radiator was supplied with power from UK National Grid. Voltage during tests was 241 V ±2 V. This produced a maximum output of approximately 1620 W, compared to the nominal stated output of 1500W. Subsequent to the test work a variable resistor was installed and the power consumption determined for various voltages as detailed below: Applied voltage Measured power (Watts) BSRIA Page 9 of 32 Final Report 54180/1

10 APPENDIX A APPENDIX: A TEMPERATURE AND POWER RESPONSE TRACES Warmup test warm up time Temperature stability Room cooling period Radiator modulating output Base load of room fans 0.5m 1.0m Globe 1.5m 2.0m 2.2m Power Temperature (oc) and power (Watts x 100) Time minutes BSRIA Page 10 of 32 Final Report 54180/1

11 APPENDIX A Warm up test 2 & 3 66% cooling load warm up time (full power) Room cooling period Temperature stability Radiator modulating output Base load of room fan 0.5 m 1.0m Globe 1.5m 2.0m 2.2m Power Tempertaure (oc) & Power (Watts x 100) Time Minutes BSRIA Page 11 of 32 Final Report 54180/1

12 APPENDIX A Time to 90% of maximum surface temperature Test Temperature (oc) minutes Air within centre column Air below column 6 Air off above column 6 Left front surface Right front surface Lower centre surface Middle centre surface Upper centre surface Internal air column 3 Air under column 1 Time (minutes) BSRIA Page 12 of 32 Final Report 54180/1

13 APPENDIX A Time to 90% of maximum surface temperature Test Temperature (oc) minutes Air within centre column Air below column 6 Air off above column 6 Left front surface Right front surface Lower centre surface Middle centre surface Upper centre surface Internal air column 3 Air under column 1 Time (minutes) BSRIA Page 13 of 32 Final Report 54180/1

14 APPENDIX A Time to 90% of maximum surface temperature Test Temperature (degc) minutes Air within centre column Air below column 6 Air off above column 6 Left front surface Right front surface Lower centre surface Middle centre surface Upper centre surface Internal air column 3 Air under column 1 Time (minutes) BSRIA Page 14 of 32 Final Report 54180/1

15 APPENDIX A Stability test 1 68% cooling load (73% of nominal stated output) m 1.0m Globe 1.5m 2.0m 2.2m Power Temperature (oc) & Power (Watts x 100) Base load of room fan Time (minutes) BSRIA Page 15 of 32 Final Report 54180/1

16 APPENDIX A Stability test 2 50% cooling load (55% nominal stated output) m 1.0m Globe 1.5m 2.0m 2.2m Power Temperature (oc) & Power (Watts x 100) Time (minutes) BSRIA Page 16 of 32 Final Report 54180/1

17 APPENDIX A Stability test 3 30% cooling load (32% nominal stated output) m 1.0m Globe 1.5m 2.0m 2.2m Power Temperature (oc) & Power (Watts x 100) Time (minutes) BSRIA Page 17 of 32 Final Report 54180/1

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19 APPENDIX B APPENDIX: B THERMAL IMAGES OF RADIATOR DURING TEST TO DETERMINE WARM UP TIME After 4 minutes After 10 minutes BSRIA Page 19 of 32 Final Report 54180/1

20 APPENDIX B After 20 minutes After 30 minutes BSRIA Page 20 of 32 Final Report 54180/1

21 APPENDIX C APPENDIX: C RADIANT TEST Radiator prior to board being positioned Front of test board BSRIA Page 21 of 32 Final Report 54180/1

22 APPENDIX C Rear of test board BSRIA Page 22 of 32 Final Report 54180/1

23 APPENDIX D APPENDIX: D TEST METHOD FREE STANDING ELECTRIC HEATERS VERSION 6 NOVEMBER 2009 BSRIA Page 23 of 32 Final Report 54180/1

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