Checking Gas Rates and Heat Inputs – Natural Gas
November 3, 2009 by carl
CHECKING GAS RATES AND HEAT INPUTS (M3)
NATURAL GAS
Where the gas meter records the gas consumption in cubic metres the following procedure should be used.
Gas Rate Procedure Meter Measuring in m3
The following procedure is just one method of calculating gas rate: -
- Turn all the appliances OFF.
- Record the meter reading. (example shows a reading of 00048.104m3)
- Turn the appliance under test to FULL ON.
- At the same time as turning the appliance on start recording the time
- When exactly two minutes have elapsed record the meter reading. (example shows a reading of 00048.188m3)
- Subtract the first reading from the second reading. This will give you the volume of gas passed in m3.
Gas rate over two minutes: -
| = | 48.188 |
| -48.104 | |
| = | 00.084 m3 |
Therefore the Gas Rate over 1 minute
| = | 00.084 m3 ÷ 2 |
| = | 0.042m3 |
So to calculate the hourly consumption, the gas rate for 1 minute is multiplied by the number of minutes in an hour.
Therefore Gas Rate/hour
| = | 0.042 x 60 |
| = | 2.52m3/hr |
We can convert this figure to cubic feet by multiplying the figure by 35.37.
Therefore 2.52 x 35.37 = 89.1324ft3/hr
Gross Heat Input = 89.1324 x 1040 = 92697 Btu/hr (27.16 KW)
To assist in the process, the chart below has been configured to provide an easy reference. It is based on a GROSS CV of 38.79MJ/m3 (1040 Btu/ft3). So in our example over a two minute period 0.084m3 is used, look at the table below for 0.080 = 2.40 m3/hr (25.8KW) and 0.004 = 0.12m3/hr (1.3KW). Add the two together 2.40 + 0.12 = 2.52m3/hr and a gross input of
25.8 + 1.3 = 27.1KW
|
GAS USED in 2 Minutes |
HOURLY RATE EQUIVALENT |
EQUIVALENT HEAT INPUT |
||
|
M3 |
M3 |
Ft3 |
kW |
Btu/hr |
|
0.001 |
0.03 |
1.06 |
0.3 |
1100 |
|
0.002 |
0.06 |
2.12 |
0.6 |
2200 |
|
0.003 |
0.09 |
3.18 |
1.0 |
3300 |
|
0.004 |
0.12 |
4.24 |
1.3 |
4400 |
|
0.005 |
0.15 |
5.31 |
1.6 |
5500 |
|
0.006 |
0.18 |
6.37 |
1.9 |
6600 |
|
0.007 |
0.21 |
7.43 |
2.3 |
7700 |
|
0.008 |
0.24 |
8.49 |
2.6 |
8800 |
|
0.009 |
0.27 |
9.55 |
2.9 |
9900 |
|
0.010 |
0.30 |
10.61 |
3.2 |
11000 |
|
0.020 |
0.60 |
21.22 |
6.4 |
22000 |
|
0.030 |
0.90 |
31.83 |
9.7 |
33000 |
|
0.040 |
1.20 |
42.44 |
12.9 |
44000 |
|
0.050 |
1.50 |
53.06 |
16.1 |
55000 |
|
0.060 |
1.80 |
63.67 |
19.3 |
65900 |
|
0.070 |
2.10 |
74.28 |
22.5 |
76900 |
|
0.080 |
2.40 |
84.89 |
25.8 |
87900 |
|
0.090 |
2.70 |
95.50 |
29.0 |
98900 |
|
0.100 |
3.00 |
106.11 |
32.3 |
109800 |
|
0.200 |
6.00 |
212.22 |
64.4 |
219700 |
Note: – Essex Heating Services accepts no liability for the accuracy of this table and the figures that it contains. You should check the data before using it to carry out any adjustments. (Please refer to the Gas Regulations before implementation – this is your responsibility).
Comments
9 Responses to “Checking Gas Rates and Heat Inputs – Natural Gas”
Feel free to leave a comment or ask a question.
nice explanation and its very detailed with graphs on it.. thank you, i like your post!
Thank you for your comment. I have been away for a little while due to the volume of work etc. I will be making a few more posts.
Regards
Well done Essex Heating on your technical data.
Regards
Alan Thomas Corgi registered commercial gas engineer ( RETIRED)
Hi Alan,
Thank you for your comment. Are there any other subjects that you feel could be added to the Blog for discussion?
How would you do it with other meters i.e the U6 or the E6,
The easiest way to Gas Rate would be to turn on the boiler and either run the hot water or central heating. Go to the Gas Meter and note the reading. Time the gas usage for 2 mins and then take a note of the reading. Take the first reading from the second and look this number up on a Gas Rating Table (these are easily available from most plumbers merchants). Just be careful to make sure that you apply the correct size to the table you are using – Cubic Metres to the Cubic Metres table – I hope this helps/
I enjoyed your comments and I thought your description were helpful
Take the first reading then after 2 min at full rate take second reading. Take the first reading from the second and then multiply by 321 gives you kw
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