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ENDUSE ANALYSIS OF ELECTRICITY APPLIANCES: END USE ANALYSIS

Posted by Connie R. Aponte on December 29, 2013 in Residential |

LT-1 and LT-2 Connections

The responses are obtained from 252 households. The data used for the analysis consists 190 (75.40%) LT-2 and 62 (24.60%) LT-1households. The average electricity consumption in LT-2 households is 4746.13 kWh/year with a standard deviation of 1230.42 kWh/year, which is more than 6 times that of LT-1 households. This has an average consumption of 203.46 kWh/year with a standard deviation 63.65 kWh/year.

Appliance Stock

The number of appliances of various types owned by LT-1 and LT-2 households differ in each category of usage such as water heating, lighting, cooking, etc. The LT-2 households mostly own appliances such as immersion rods, geysers, refrigerators, computers and water pumps. Education

On the other hand none of the LT-1 households own geysers, pumps and refrigerators. Figure 3 gives the difference in proportion of households using appliances such as immersion
Fig3Enduse Analysis of Electricity-3

Rods (IR), Fans, television (TV), 40 W fluorescent lamp (FL), incandescent lamps (IL), Compact Fluorescent Lamps (CFL), which are common to both LT-1 and LT-2 categories. In the LT-2 category, 100% of the households have televisions whereas in the LT-1 households, the penetration of TVs is about 70.97%. Air coolers are more prominent along with fans among the LT-2 households (100%), the share of fans in LT-1 households is 77.42%. A larger proportion of households in the LT-1 category use 100 W and 60 W incandescent lamps but a larger proportion of LT-2 homes use fluorescent tubes and 20 W CFLs as indicated in the figures 4 and 5.

The indication from the results shows that even though incandescent lamps are a common feature in both LT-1 and LT-2 households, the number of bulbs per 100 households varies from 200 bulbs in LT-1 to 162 bulbs in the LT-2 category. In the case of fluorescent tubes, the average number per 100 households is 142 for LT-1 whereas it is 200 for LT-2.

Engineering Approach

The engineering approach is based on the number of appliances, Nij, the wattage, Pij, and hours of usage, Tij of the appliance j reported by the sample household i during the survey. The total electricity consumption in a household
Fig4-5Enduse Analysis of Electricity-4
E= IEi

i can be related thus to the appliance-wise consumption: where Eij is the electricity consumed by the jth appliance

E = N * C

i Nii Cii

in the ith household. Also, in the ith household,  where Cij is the electricity consumption of the jth appliance category and Nij is the number of electrical appliances in the jth category. Cij can be written as

C — P * T

Cii pi ii

Where Pij the wattage of the jth appliance category and Tij is the number of hours per month for which the jth appliance is being used. The Cij, referred to as the engineering estimate of the appliance consumption depends upon the accuracy of determination of the hours of usage.

Substituting Cij in the previous equation, the following expression is obtained for the electricity consumption of the ith household:
E = У N~ * P * T

The survey data on appliance stock, rating in watts and hours of usage, gives the engineering estimates of the household consumption. These estimates were calculated for each of the appliance categories in both LT-1 and LT-2 households and the results are shown in figures 6 and 7. Lamps (incandescent and fluorescent), fans, fridge, geyser, immersion rod and ovens are
Fig6-7Enduse Analysis of Electricity-5

estimated to consume 78.89% of the average electricity consumption per LT-2 house. In contrast, lamps, fans, television, water heating and electric iron are estimated to consume 95.4% of the average electricity consumption per household in the LT-1 category. For the end-use of lighting, LT-1 households consume a high percentage (18.14%) of the average electricity consumption per household when compared to LT-2 households (12.79%).

Appliance Stock Approach

W4 = У (N>i, P)
table4Enduse Analysis of Electricity-6
The electricity consumption in a household is determined by its stock of electrical appliances. If Nij and Pij are the number and wattage of electric appliances of the jth category in the ith household, then Nij*Pij would be the electrical load in watts due to this category of appliances. It follows that must be the total electrical load in watts due to this category of appliances. It is reasonable to expect the electrical energy consumption Ei (in kWh) of households is correlated with their loads Wi (in kW). When the yearly electricity consumption was regressed on the household load, the result was Ei = 3515 + 25.64 Wi and R2 = 0.326. From this we can conclude that a unit increase in load results in an increase of 25.64 kWh per year in electricity consumption. The actual increase would be different if the coincidence factor of using the appliances at the same time is taken into account. Also, the household load due to its appliance stock explains only 32.6% of the variation.

Appliance Census Approach

In the appliance census approach the relationship used to estimate the monthly electricity consumption of the jth appliance category is given by

Еч = У Nj * Д.

j

Here, Aj is the consumption per appliance of the jth category, which can be estimated by regressing the electricity consumption Ei on the number of appliances Nij of the jth category in the ith household. Here, the coefficient Aj is the marginal consumption of the jth appliance category, that is, the increase in consumption resulting from the addition of one appliance of the jth category. The marginal and the average consumption of the jth appliance category can be considered as identical, as a linear relation between the consumption and the number of appliances of a particular category is expected.

Using the above relationship, regression analysis was carried out on the samples of LT-1 and LT-2 households separately. The result of the stepwise regression analysis on the LT-2 households is given in table 3. The result indicates a R2 value of 0.62, meaning that 62% of the variation in electricity consumption among the LT-2 houses is explained by the 12 categories of appliances included in the model.

Similarly, a step-wise regression analysis was performed on the LT-1 sample households. The result in table 3 indicates a R2 value of 0.31 explaining 31% of the variation in the electricity consumption by the 7 categories of appliances in the LT-1 houses.

The results show that immersion rods, TV and ILs are highest electricity consuming appliances in LT-1 households, consuming 998.71, 348.39 and 949.94 kWh per year respectively. In LT-2 households, as shown in table 4, refrigerators and water heaters (geysers and immersion rods) and fans consume the most electricity with 1163, 663.15 and 574.5 kWh per year respectively. The implied usage hours thus obtained from the regression analysis makes much better sense when compared to the user reported hours.

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