IV. SYSTEM DATA AND RESULTS
The load management programs, which mainly focus on
reduction of load demand is an effective tool to handle the
peak demand deficit faced by the utilities. The effectiveness
of the BMS installed in the buildings of the main campus of
KAU in the reduction of energy consumption is presented in
this section with reference to the Building No. 51. This
building space is utilized by the staff of the Security and
Safety Department of the University, and hence the offices are
occupied by the staff irrespective of the months of regular
class or vacation periods. This building has 31 office rooms
and one conference hall, and each of these rooms have been
provided with a mi-range occupancy sensor. Building No. 51
has eight AHUs each of 25 TR rating, each unit catering to the
ac requirements of separate groups of four rooms. These
AHUs are provided with damper actuators and the sensors for
duct temperature and air quality. The compressor motors of all
the eight AHUs have been changed over to variable frequency
drives of power rating 5.5 kW so as to enable the adjustment
of the motor speed as the thermostat setting of AHUs are
varied and thus improve the motor efficiency. The total
connected HVAC and lighting load of 748 kW in the building
is controlled through two separate DDC panels.
The electrical load demand data along with the phase voltages
and currents of the buildings are monitored continuously at 30
minutes intervals throughout the day and thus throughout the
year. These instantaneous interval data stored in the digital
meters are later transferred to the personal computers for
further analysis. The charts of average power demand obtained
from the interval data corresponding to the months of August
2011 and August 2012 are given in Fig. 5 and Fig. 6
respectively. The results corresponding to August 2011 are
obtained from the data before the installation of BMS in the
building, and that corresponding to the month of August 2012
from the data after the installation. It can be observed from
these figures that trend of energy consumption in this building
corresponding to any specific day in each week of these
months, in general follows the similar pattern. Further, the
energy consumption on Fridays are seen to be lesser than the
other days in both these months. This is because Fridays are
holidays. The effect of BMS in the building can be clearly seen
from the energy consumption results corresponding to Fridays
in these months. The results given in Fig. 6 corresponds to the
AHU thermostats so set as to have the room temperature of
20ºC during the day time schedule from 6.00 a.m. to 12.00
midnight and 24ºC during night time schedule from 12.00
midnight to 6.00 a.m. The speed of VFDs are set to 50% in the
night when the temperature setting is increased. On the other
hand, in August 2011, the thermostats are set to 20ºC and the
motors run at 100% speed throughout the day. Upon
comparison of Fig. 5 and Fig.6, It can be deduced that the
energy consumption in the building on holidays could be
significantly reduced with BMS. Further, it can be deduced
from Fig.7 that the average power demand in the month of
August 2012 is significantly less than that in August 2011 in
most of the days. Total energy consumption in these months
are 58883.2 kWh and 50456.0 kWh respectively, and thus the
saving in energy consumption the month of August 2012 after
the installation of BMS is to the tune of 14.31% when
compared to that of August 2011, a month with no BMS. The
major contributing factor to this reduction in the load demand
is the reduction in the air conditioning and the lighting loads
on these days achieved through the automatic monitoring and
control by the BMS. It is possible to further conserve energy by
appropriate fine tuning and book-keeping of the BMS
operation.
IV. SYSTEM DATA AND RESULTS
The load management programs, which mainly focus on
reduction of load demand is an effective tool to handle the
peak demand deficit faced by the utilities. The effectiveness
of the BMS installed in the buildings of the main campus of
KAU in the reduction of energy consumption is presented in
this section with reference to the Building No. 51. This
building space is utilized by the staff of the Security and
Safety Department of the University, and hence the offices are
occupied by the staff irrespective of the months of regular
class or vacation periods. This building has 31 office rooms
and one conference hall, and each of these rooms have been
provided with a mi-range occupancy sensor. Building No. 51
has eight AHUs each of 25 TR rating, each unit catering to the
ac requirements of separate groups of four rooms. These
AHUs are provided with damper actuators and the sensors for
duct temperature and air quality. The compressor motors of all
the eight AHUs have been changed over to variable frequency
drives of power rating 5.5 kW so as to enable the adjustment
of the motor speed as the thermostat setting of AHUs are
varied and thus improve the motor efficiency. The total
connected HVAC and lighting load of 748 kW in the building
is controlled through two separate DDC panels.
The electrical load demand data along with the phase voltages
and currents of the buildings are monitored continuously at 30
minutes intervals throughout the day and thus throughout the
year. These instantaneous interval data stored in the digital
meters are later transferred to the personal computers for
further analysis. The charts of average power demand obtained
from the interval data corresponding to the months of August
2011 and August 2012 are given in Fig. 5 and Fig. 6
respectively. The results corresponding to August 2011 are
obtained from the data before the installation of BMS in the
building, and that corresponding to the month of August 2012
from the data after the installation. It can be observed from
these figures that trend of energy consumption in this building
corresponding to any specific day in each week of these
months, in general follows the similar pattern. Further, the
energy consumption on Fridays are seen to be lesser than the
other days in both these months. This is because Fridays are
holidays. The effect of BMS in the building can be clearly seen
from the energy consumption results corresponding to Fridays
in these months. The results given in Fig. 6 corresponds to the
AHU thermostats so set as to have the room temperature of
20ºC during the day time schedule from 6.00 a.m. to 12.00
midnight and 24ºC during night time schedule from 12.00
midnight to 6.00 a.m. The speed of VFDs are set to 50% in the
night when the temperature setting is increased. On the other
hand, in August 2011, the thermostats are set to 20ºC and the
motors run at 100% speed throughout the day. Upon
comparison of Fig. 5 and Fig.6, It can be deduced that the
energy consumption in the building on holidays could be
significantly reduced with BMS. Further, it can be deduced
from Fig.7 that the average power demand in the month of
August 2012 is significantly less than that in August 2011 in
most of the days. Total energy consumption in these months
are 58883.2 kWh and 50456.0 kWh respectively, and thus the
saving in energy consumption the month of August 2012 after
the installation of BMS is to the tune of 14.31% when
compared to that of August 2011, a month with no BMS. The
major contributing factor to this reduction in the load demand
is the reduction in the air conditioning and the lighting loads
on these days achieved through the automatic monitoring and
control by the BMS. It is possible to further conserve energy by
appropriate fine tuning and book-keeping of the BMS
operation.
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