Ensayos de permeabilidad durante la perforación

The electricity demand profile data for the case

study residential building in Nigeria was carried out by installing a Demand Profile Recorder (DPR)

shown below in the case study building. The

obtained energy data was matched against the

generated electricity and recoverable heat of a CHP system to determine the pattern of operation of the

system in a residential application. The demand

pattern is one of the crucial factors in the

determination of the practicality of installing a

small scale Combined Heat and Power unit in a b u i lding.

FIG 6.7 D E M A N D P R O F I L E R E C O R D E R

During the field work, it was observed that most residential building services appliances in Nigeria operate on electricity (including Air Conditioning

and Hot Water Services) . Some buildings were

equipped with dual fuel cooking appliances that

operate on both Natural gas and electricity,

however bottled gas is only used as an alternative fuel source when there is a power f a i l u r e .

All appliances in the case study building operate on electricity. This is made possible because the building is installed with a standby electricity generator for use when mains fail.

Table 6.3 shows the measured electricity demand profile for the building. The weekday and weekend profile indicated in the table was the average demand for each hour over a two week period.

From the evaluation in section 6.1, the installed electricity capacity for the building, including

air conditioning and Hot W a t e r Services is

approximately 74k W e . The actual demand varies

according to equipment load over the twenty-four hour period, as shown in the graph of figure 6.8.

During a weekday, the actual load between 0700

hours and 1000 hours is a combination load of air

conditioning, hot water and cooking loads.

There was a continuous shedding of loads by the switching off of air conditioners and lights in

each room after a peak period at 0700 hours, although other loads such as for cooking breakfast and hot water heater take up part of the reduced load for the time.

TIME WEEKDAY WEEKEND TIME WEEKDAY WEEKEND

(HRS) (kWe) (kWe) (HRS) (kWe) (kWe)

0700 31 33 1900 20 21 0800 24 28 2000 28 28 0900 15 26 2100 33 31 1000 12 19 2200 42 40 1100 6 15 2300 40 39 1200 5 15 2400 3 9 37 1300 4 12 0100 38 40 1400 4 13 0200 35 32 1500 6 10 0300 30 28 1600 19 12 0400 27 29 1700 24 14 0500 28 28 1800 21 17 0600 30 32 TABLE 6.3 m e a s u r e d e l e c t r i c i t y d e m a n d (f o r c a s e s t u d y b u i l d i n g) PROFILE

The demand level is at m inimum between 1000 and 1500 hours of the day, because the building is lightly o c c u p i e d . The only power consumption was noted to be by the refrigerators and deep freezers in the building.

At 1600 hours, the demand level gradually starts to increase, because the children start to return from school. Also the domestic staff begin preparation of the evening meals for the family. At this time, the air conditioning units are switched on in

certain parts of the building, especially the play area and common room such as the sitting room. The demand continues to increase until 2000 hours at n i g h t . o o a TIME (HRS) I WEEKDAY WEEKEND FIG 6 . 8 B U I L D I N G E L E C T R I C I T Y D E M A N D P R O F I L E G R A P H

The unexpected increase in demand from 2100 hours has been identified to the increase in the number of air conditioners switched on in individual rooms as members of the household retire for the night.

This load fluctuates and decreases towards 0600

hours the next morning as the outside air

temperature decreases. Since the air conditioners are controlled by room sensor thermostats, the fans re-circulates the room air while cooling is halted, until such time as the room air temperature is sensed again to be above the set point.

The electricity demand for running the air

conditioners decreases in accordance with the

length of time this idling takes p l a c e . This method of operation continues until 0700 hours, when the occupants of the building start leaving their rooms and switch off the air conditioners in preparation for the new d a y ’s activities.

At the weekend, the demand profile is similar to that of weekdays except the demand load does not start to decrease until about 1000 hours, because the occupants stay late in their bedrooms. As a

result of this, most air conditioners in the

building will remain in operation until after 1000 h o u r s .

Also during the low activity period of 1100 to 1400

hours, the demand profile of the weekends was

slightly higher than the weekdays because more people were in the building. This will result in the operation of some of the air conditioners, and

home entertainment accessories powered by

electricity, adding to the building electricity

d e m a n d .

To determine the load demand of the building in relation to the application of a small scale CHP unit, the air conditioning and hot water services load

W E E K D A Y W E E K E N D