Case Study - Energy Audit of UCD Student Centre 2 pg

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Description

Comprehensive Energy Survey of UCD Student Centre Summary UCD Building & Services Department commissioned PowerTherm to undertake a comprehensive energy survey of the one year old Student Centre. The objectives of the survey were to establish if energy consumption levels were high by comparison with similar buildings; analyse how energy was being consumed at the site; and identify cost-effective energy saving measures. The survey concluded that energy consumption levels were slightly above average; provided a detailed energy tree illustrating how energy was consumed; and identified cost-effective measures that could reduce total annual energy costs by 21%. Site Description The Student Centre consists of a 4,000 sqm building, a pedestrian walkway and a car park. Within the building are offices, meeting rooms, retail units, restaurants, a bar, a multi-purpose hall, and a central social space. Ventilation is provided by air handling units, extract fans, and openable windows. Heat for central heating and domestic hot water consumption is provided by the campus’ combined heat and power plant. Heat is delivered via radiator circuits and heating batteries in the air handling units. The operation of exterior lights, ventilation and heating systems is controlled by UCD’s Building Management System (BMS), with local operator interface. The BMS also meters heat and power consumption for the building, with submeters for the restaurant, retail units, ...

Informations

• Publié par: Obbi
• Nombre de lectures: 12
• Langue: English

Extrait

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Comprehensive Energy Survey of UCD Student Centre

Summary

UCD Building & Services Department commissioned PowerTherm to undertake a comprehensive

energy survey of the one year old Student Centre. The objectives of the survey were to establish

if energy consumption levels were high by comparison with similar buildings; analyse how energy

was being consumed at the site; and identify cost-effective energy saving measures. The survey

concluded that energy consumption levels were slightly above average; provided a detailed

energy tree illustrating how energy was consumed; and identified cost-effective measures that

could reduce total annual energy costs by 21%.

Site Description

The Student Centre consists of a 4,000 sqm building,

a pedestrian walkway and a car park. Within the

building are offices, meeting rooms, retail units,

restaurants, a bar, a multi-purpose hall, and a central

social space.

Ventilation is provided by air handling units, extract

fans, and openable windows. Heat for central heating

and domestic hot water consumption is provided by

the campus’ combined heat and power plant. Heat is

delivered via radiator circuits and heating batteries in

the air handling units. The operation of exterior lights,

ventilation and heating systems is controlled by

UCD’s Building Management System (BMS), with

local operator interface. The BMS also meters heat

and

power

consumption

for

the

building,

with

submeters for the restaurant, retail units, and bar.

Data Collection

Daily historical data was

available

from

UCD

for

building heat and power

consumption.

This

was

combined

with

daily

average

ambient

air

temperatures to evaluate

seasonal

differences,

including daily hot water

requirements.

A log was established to

automatically record meter

and submeter readings on

a 15-minute basis over a

period of 2 weeks. The

data was charted and load

changes over the course of

a day, and on different

days were assessed.

Bar Electric Load Profile

0

1

2

3

4

5

6

7

8

9

0:15

2:00

3:45

5:30

7:15

9:00

10:45

12:30

14:15

16:00

17:45

19:30

21:15

23:00

No.ofkWhper15mininterva

26-Jul-02

27-Jul-02

28-Jul-02

29-Jul-02

30-Jul-02

31-Jul-02

01-Aug-02

02-Aug-02

03-Aug-02

Seasonal Heating Loads

0

10,000

20,000

30,000

40,000

50,000

60,000

J

u

n

J

u

l

y

A

u

g

S

e

p

t

O

c

t

N

o

v

D

e

c

J

a

n

F

e

b

M

a

r

A

p

r

M

a

y

Heat Consumption (kWh)

0

50

100

150

200

250

300

350

400

Heat Cost (kWh)

Deg Days (15.5

base)

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In addition, the building design drawings, the services engineer’s calculations, and the installation

manuals were reviewed to collect information on the building size and lighting, heating pumps and

ventilation motor operating loads. The BMS provided operating load information for some of the drives

and, where necessary, an ammeter was used to verify the current drawn by some of the drives. The

BMS schedule of all lights and drives was interrogated. The building managers were questioned as to

the building occupancy period and normal operating schedule of manually controlled loads (such as

interior lights and office equipment). All this information was incorporated into a spreadsheet model to

gain an understanding of loads attributable to lighting, heating, ventilation and other equipment.

Analysis

The analysis first compared the relative energy

consumption of heat, gas and electricity.

Energy

consumption

was

then

compared

with

benchmarks for similar buildings, using Irish and UK

energy consumption data. This helped in assessing

the extent to which energy savings could be realised

from the building.

The energy tree, below, was prepared to illustrate

where energy was consumed. It helped identify the

areas

which

consumed

most

energy,

thereby

prioritising in which areas to look for energy savings.

The analysis also reflected

on the electrical load types.

For instance, it was found

that 36% of the building’s

energy consumption was due

to a low level of continuous

base load, whereas only 2%

was due to high levels during

the

short

lunchtime

peak

period.

This base load then became

the subject of further analysis

in order to establish what was

contributing to it.

Conclusions

The conclusion of the report identified 30 measures for energy saving, including housekeeping

measures, building management and monitoring measures, modifications to the BMS control, and

investments in equipment. The cost of investments were estimated, along with the likely value of the

resulting energy saving. The total value of energy savings identified amounted to 21% of the annual

energy bill (figures were adjusted down to avoid any overlap in the net effect of energy saving

measures). All measures had a paypack period of less than 4 years, with the majority of measures

having little or no cost.

The total cost of this detailed energy survey was 5.5% of the annual energy bill.

Fig. 22: Electrical Load Types

Base Load

36%

Building Opening Load

17%

Building Occupancy Load

25%

Lunchtime Peak

2%

Exterior Lights

19%

Unaccounted

1%

Annual Energy Consumed [kWh]

52%

2%

46%

Electricity

Gas

Heat