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Calculating Payback Periods for Energy Efficiency Improvement Applications

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 Çukurova Üniversitesi Mühendislik Mimarlık Fakültesi Dergisi, 30(1), 41-56 ss., Haziran 2015
Çukurova University Journal of the Faculty of Engineering and Architecture, 30(1), pp.41-56 , June 2015

Calculating Payback Periods for Energy Efficiency Improvement

Applications at a University Hospital

Ahmet TEKE*1, Oğuzhan TİMUR1, Kasım ZOR2

1
Ç.Ü., Mühendislik-Mimarlık Fak., Elektrik-Elektronik Mühendisliği Bölümü, Adana
2
Adana Bilim ve Teknoloji Üniversitesi, Elektrik-Elektronik Mühendisliği Bölümü, Adana
Geliş tarihi: 03.03.2015 Kabul tarihi: 17.04.2015

Abstract

The increasing demand for energy and the depletion of existing fossil fuel based resources have forced
the countries to realize the efficient use of energy, energy saving applications and searching alternative
energy sources. Using the energy efficiently and performing energy saving studies have great importance
for developing countries like ours that are dependent on other countries to meet their energy needs.
Hospitals generally consume 6% of total energy in the buildings. Heating, Ventilation and Air
Conditioning (HVAC) systems are the significant part of electrical energy consumption at the hospitals.
The air-conditioning system is responsible for around 70% of total electricity consumption. Electric
motors and lighting systems in a hospital represent approximately 19-21% of the total energy
consumption. In this study, according to the detailed analysis on the lighting devices, electric motors and
HVAC systems, the energy saving potentials and payback periods of these systems are estimated for a
University Hospital.

Keywords: University hospital, Energy efficiency, Energy saving, Energy management.

Bir Üniversite Hastanesinde Enerji Verimliliğini Artıran Uygulamaların Geri

Dönüşüm Sürelerinin Hesaplanması
Özet

Artan enerji talebi ve mevcut fosil yakıt tabanlı kaynaklarının hızla tükenmesi, ülkelerin enerjiyi verimli
kullanmasına, enerji tasarrufu yapmasına ve alternatif enerji kaynaklarını aramasına zorlamıştır. Enerji
ihtiyaçlarını karşılamada başka ülkelere bağımlı olan bizim gibi gelişmekte olan ülkelerde, mevcut
enerjiyi verimli kullanmak ve tasarruf çalışmaları yapmak daha büyük önem taşımaktadır. Hastaneler
binalarda kullanılan toplam enerjinin yaklaşık olarak %6’sını tüketmektedir. Isıtma, Havalandırma ve
İklimlendirme sistemleri (IHİS), hastanede tüketilen elektrik enerjisinin büyük bir kısmını
oluşturmaktadır. İklimlendirme sistemleri toplam tüketilen yaklaşık olarak %70’inden sorumludur.
Hastanedeki elektrik motorları ve aydınlatma sistemleri yaklaşık olarak toplam enerjinin %19-21‘lik
kısmını harcamaktadırlar. Bu çalışmada, aydınlatma cihazları, elektrik motorları ve IHİS sistemleri
üzerine yapılan detaylı çalışmalar sonucunda, bir üniversite hastanesinde bu cihazların enerji tasarruf
potansiyelleri ve geri dönüşüm süreleri tahmin edilmiştir.

Anahtar Kelimeler: Üniversite hastanesi, Enerji verimliliği, Enerji tasarrufu, Enerji yönetimi.

*
Yazışmaların yapılacağı yazar: Ahmet TEKE, Ç.Ü., Mühendislik Fakültesi, Elektrik-Elektronik
Mühendisliği Bölümü, Adana. ahmetteke@cu.edu.tr

Ç.Ü.Müh.Mim.Fak.Dergisi, 30(1), Haziran 2015 41

Calculating Payback Periods for Energy Efficiency Improvement Applications at a University Hospital

1. INTRODUCTION consumer in these types of buildings. It accounts

for almost 60% of total energy cost in a building
Hospitals account for a remarkable ratio of the [9]. The energy consumption distribution of a
total energy consumption in the utility buildings hospital can be classified by electrical energy
sector, due in large part to the very high energy consumption types. HVAC (especially cooling and
intensity levels of hospitals and other inpatient ventilating) systems are the major part of electrical
care facilities [1]. Energy efficiency studies can be energy consumption. If the absorption chiller is not
divided into four main categories in the hospitals. in use, then the air-conditioning system is
These categories are lighting, electric motors, responsible for around 70% of total electricity
HVAC and other systems. 20% of total world consumption. Among them, the chillers, the chilled
electricity consumption is approximately water pumps and the fan of the cooling towers
consumed by lighting. Energy efficient lighting is would need 43.94% of the total electricity [10].
one of the best and most cost effective way to The use of energy efficient electric motors and
reduce total energy consumption in the world. It is variable speed (frequency) drive (VSD) systems
very important to evaluate and change current are the best and most cost effective ways to reduce
lighting system to satisfy energy efficient lighting. total electrical energy consumption especially in
Lighting systems consist of four physical HVAC system at the hospitals [10], [11]. What
components namely lamp, fixture, ballast and appears as a problem in most papers is the lack of
control system. Each component affects energy use evaluation of savings opportunities and payback
and annual cost of the lighting system. The energy period calculations; in other words, even in the
consumption of each component is very important research results where it is indicated how much
for the energy efficiency researches. The selection energy can be saved by using the energy saving
of more efficient material and equipment will studies discussed [12]. In this study, the energy
reduce the electricity consumption and increase the saving potentials are investigated by calculating
energy efficiency. For energy saving in lighting, payback times at a university hospital in Turkey.
lamp types and their characteristics should be
known in detail [2-3]. Old or inefficient lamp types 2. ENERGY EFFICIENCY and ENERGY
should be changed with new and efficient lamp SAVING OPPORTUNITIES at
types. In the new installed buildings, LED lamps UNIVERSITY HOSPITAL
should be preferred by calculating payback time.
Energy efficiency improvement projects can
reduce the utility bill costs and operations and
Approximately 65% of total electricity
maintenance costs. There are numbers of energy
consumption is consumed by electric motors in
efficiency improvement applications for lighting,
Turkey [4]. In addition, about 35% of total energy
motors, VSDs and HVAC systems. Some energy-
is used in the industrial sector in Turkey [5]. In the
efficiency improvement projects may not be
world, an industrial sector uses more energy than
economically feasible. Simple payback method is
any other end-use sectors and currently this sector
preferred for payback period calculations. This
is consuming about 37% of the world’s total
method uses a period of time in which a project’s
delivered energy [6]. Electric motors in a hospital
energy savings should equal the amount of money
represent approximately 19% of the total energy
invested [3, 13].
consumption. More than 95% of all motors in the
industry are AC induction motors. In Turkey, the
most of electricity energy in industry sector is 2.1. Implemented and Suggested Projects for
consumed by AC motors as elsewhere in the other Lighting Systems
countries. Motor electricity consumption by end-
use in industrial sector are 22% fan, 29% pump, Lighting systems can be investigated as exterior
7% compressor and 42% others devices [7-8]. lighting and interior lighting systems. Especially,
HVAC systems are the single largest energy at the exterior lighting, expensive and high density

42 Ç.Ü.Müh.Mim.Fak.Dergisi, 30(1), Haziran 2015

 Ahmet TEKE, Oğuzhan TİMUR, Kasım ZOR

luminance lamps (mercury vapor or metal halide The saving kWh in a year can be calculated as
lamps) are used for environmental and road 13,908 and saving TL can be calculated 4,451 TL.
lighting. These lamps are consumed electric Installed cost of new armature and lamps labor
energy more than new lamps led or compact included price are 40x110=4,400 TL. As a result,
fluorescent. Most of the lamps used for interior payback period can be calculated 0.99 year.
lighting of hospital are CFLs with magnetic
ballast. CFLs with electronic ballast should be  Replacement mercury lamps with the CFL
preferred instead of old type magnetic ballast. and LED: In the hospital, the total installed
capacity of mercury lamps for exterior lighting is
2.1.1. Exterior Lighting at University Hospital approximately 5 kW at the back side of the
parking. Table 3 shows the total energy savings in
The lamps used for the exterior lighting at a year when the 250W mercury lamps are replaced
University Hospital are as shown in Table 1. with 45 W CFL lamps. Mercury lamps have 10%
ballast losses and CFL lamps have 8% electronic
Table 1. Exterior lighting at University Hospital ballast losses. The running time of exterior lighting
lamps is 11 hours in a day. According to peak and
Metal halide

night time period, the average electricity unit price

CFL (23W)

Fluorescent
Mercury

Mercury
(125 W)

(250 W)

(750W)

(18W)

for kWh is approximately 0.32 TL. A year will be

vapor

vapor

Place/Pcs. taken 360 days. If total 20-pcs of mercury lamps

are replaced with 45 W CFL, total saving kWh can
be calculated as 17,931 kWh and total saving TL
Back side of can be found 5,738 TL. As a result, payback period
20 20 8 - -
parking
is calculated as 0.17 year = 2.04 months.
Front side
16 - - - -
of parking
Refectory Calculations:
exit under - - 2 50 -
the viaduct Total = 20
Viaducts of consumption x250/1,000x11x360x1.1
Blood 34 - - - of 250 W
center Mercury lamp
Emergency = 21,780 kW
9 - 8 -
exit Total = 20x45/1,000x11x360x1.08
Cafeteria consumption
under the - - - - 72 of 45 W CFL
viaduct
= 3,849.12 approx. 3,849
Total Saving kWh in = 21,780-3,849
79 20 18 50 72
number
a year
Consumption
9,875 5,000 13,500 1,150 1,296 = 17,931 kWh
of lamps
Saving TL = Saving kWh x Electricity unit
Total Cons. 30,821 in a year price
= 17,931x0.32 TL = 5,738 TL.
 Replacement 40-pcs 125 W mercury lamps Payback = Total installed cost / Total
with 40-pcs 2x23 W CFL lamps: At the exterior time (year) saving TL.
lighting, there are 40-pcs 125 W mercury lamps in = (Lamp cost x # of lamp) /
front of blood center. Mercury lamps have 10% Total saving TL.
ballast losses and CFL lamps have 8% ballast = (50x20) / 5,738 = 0.17 year
losses (electronic-type). 2-pcs 23 W fluorescent Payback 0.17
= x 12 = 2.04 months
lamps and armature cost are 110 TL including all time
taxes as illustrated in Table 2. (month)

Ç.Ü.Müh.Mim.Fak.Dergisi, 30(1), Haziran 2015 43

Calculating Payback Periods for Energy Efficiency Improvement Applications at a University Hospital

Table 2. The implemented project for exterior lighting system

Savings/year (TL)
consumption (W)

Investment cost

Payback period
Unit cost (TL)

Savings/year
# of lamps

hours/day

kWh/year
days/year
Energy

(kWh)

(year)
(TL)
Lamp type

125 W Mercury lamp 137.5 W 40 11 360 21,780 - - - - -

2x23 W CFL 49.7 W 40 11 360 7,872 110 4,400 13,908 4,451 0.99

Table 3. The planned project_1a for exterior lighting system

consumption (W)

Investment cost

Payback period
Unit cost (TL)

Savings/year

Savings/year
# of lamps

hours/day

kWh/year
days/year
Energy

(kWh)

(year)
(TL)

(TL)
Lamp type

250 W mercury lamp 275 20 11 360 21,780 - - - - -

45 W CFL 48.6 20 11 360 3,849 50 1,000 17,931 5,738 0.17

Table 4. The planned project_1b for exterior lighting system

Investment cost

Payback period
Unit cost (TL)
consumption

Savings/year

Savings/year
# of lamps

hours/day

kWh/year
days/year
Energy

(kWh)

(year)
(TL)

Lamp type (TL)

250 W mercury lamp 275 W 20 11 360 21,780 - - - - -

65 W LED 68.9 W 20 11 360 5,457 472 9,440 16,323 5,223 1.81

Table 5. The planned project_2 for exterior lighting system

Savings/year (TL)
Investment cost

Payback period
Unit cost (TL)
consumption

Savings/year
# of lamps

hours/day

kWh/year
days/year
Energy

(kWh)

(year)
(TL)

Lamp type

23 W CFL 24,84 W 50 11 360 4,918 - - - - -

7.5 W LED 7,95 W 50 11 360 1,574 35,4 1,770 3,344 1,070 1.65

44 Ç.Ü.Müh.Mim.Fak.Dergisi, 30(1), Haziran 2015

 Ahmet TEKE, Oğuzhan TİMUR, Kasım ZOR

Table 6. The planned project_3a for exterior lighting system

Investment cost

Payback period
Unit cost (TL)
consumption

Savings/year

Savings/year


# of lamps

hours/day

kWh/year
days/year
Energy

(kWh)

(year)
(TL)

(TL)
Lamp type

18 W Fluorescent 23,4 W 72 11 360 6,671 - - - - -

7.5 W LED 7.95 W 72 11 360 2,267 35,4 2,549 4,404 1,409 1.8

As shown in Table 4, if the 20-pcs of mercury conventional fluorescent lamps are converted to
lamps are replaced by 65 W LED armature. The fluorescent lamps with electronic ballast for 18W
cost of a LED armature is 472 TL. LED lamps system, it is enough to change ballasts.
have approximately 6% losses. As shown in Approximately medium quality electronic ballast
Table 4, payback time will be found 1.81 years as cost is 7 TL (All taxes are included to this price).
a result of this replacement. The replacement of After the calculations, payback time will be found
the mercury lamp with the CFL is more feasible 3.6 years as shown in Table 7.
than the replacement of the mercury lamp with the  Replacement 750 W metal halide lamps with
LED armatures. LED lamps: At the exterior lighting, there are 18-
 Replacement CFL with LED lamps: At the pcs metal halide lamps. 24 number 120 W LED
exterior lighting, there are 50-pcs 23 W CFLs at lamps will be used instead of 18-pcs 750W metal
the refectory exit under the viaduct. CFL lamps halide lamps. Metal halide lamps have 14% losses
have 8% losses and LED lamps have 6% losses. and LED lamps have 6% losses. As shown in
As shown in Table 5, when 23 W CFLs are Table 8, energy saving in a year can be calculated
replaced with 7.5 W LED lamps, saving TL in a 48,924 kWh and period time can be calculated
year can be found 1,070TL and payback are found 1.04 years. At the hospital, the most of the exterior
1.65 year. lighting armatures are controlled by the day light
Replacement Fluorescent Lamp with LED sensor with the time relay. The using of these
lamps: At the exterior lighting, there are 72-pcs 18 automatic controlled systems is more efficient than
W fluorescent lamps with old type magnetic manual controlled systems. The total estimated
ballast at the cafeteria under the viaduct. 18 W energy saving as kWh for exterior lighting is
fluorescent lamps with the magnetic ballast have 75,630 kWh. Total investment for these projects is
30% ballast losses and LED lamps have 6% losses. 21,639 TL. The payback periods of feasible
As shown in Table 6, when 72-pcs 18 W projects is changed between 0.17 and 2.35 as
fluorescent lamps with the conventional magnetic shown in Table 9.
ballast are replaced with the 72-pcs 7.5 W LED
lamps, 1,409 TL will be saved in a year and 2.1.2. Interior Lighting at University Hospital
payback time will be found 1.8 year.
Most of the interior lightings armatures at
 Replacement of conventional fluorescent University Hospital are conventional fluorescent
lamp with fluorescent lamp with lamps with the magnetic ballast. Fluorescent lamps
electromagnetic ballast: At the exterior lighting, with electronic ballast have been only used in old
there are 72-pcs 18 W fluorescent lamps with intensive care and there are 220-pcs 2x40 W
magnetic ballast at the cafeteria. 18 W fluorescent fluorescent lamps with electronic ballast. Total
lamps with old type magnetic ballast have 30% capacities of them are 17,600 W. At the some units
ballast losses and 18 W fluorescent lamps with of the hospital such as in the air conditioner center,
electronic ballast have 8% ballast losses. While the different types of lamps are used. But this situation

Ç.Ü.Müh.Mim.Fak.Dergisi, 30(1), Haziran 2015 45

Calculating Payback Periods for Energy Efficiency Improvement Applications at a University Hospital

Table 7. The planned project_3b for exterior lighting system

period (year)
consumption

Savings/year

Savings/year
Investment
# of lamps

hours/day

kWh/year
days/year

cost (TL)
Unit cost

Payback
Energy

(kWh)
(TL)

(TL)
Lamp type

18 W Fluorescent 23.4 W 72 11 360 6,671 - - - - -

18 W Fluorescent with
72 11 360 5,531 7 504 1,140 364 1.4
electronic ballast 19.4 W

Table 8. The planned project_4 for exterior lighting system

period (year)
consumption

Savings/year

Savings/year
Investment
# of lamps

hours/day

kWh/year
days/year

cost (TL)
Unit cost

Payback
Energy

(kWh)
(TL)

(TL)
Lamp type

750 W Metal Halide 855W 18 11 360 60,994 - - - - -

120 W LED lamps 127W 24 11 360 12,070 680 16,320 48,924 15,656 1.04

Table 9. Feasible projects for exterior lighting used for two types of system. Because of this,
there is no requirement for new armatures. As
Project Energy Energy Investment Payback shown in Table 10, 250 W mercury lamps have
number saving saving TL period 10% ballast losses and 45 W CFL lamps have 8%
kWh/year TL year losses. 16 lamps operate 24 hours in a day for
1a 17,931 5,738 1,000 0.17 360 days in a year. Electricity unit price for kWh
1b 16,323 5,223 9,440 1.81 can be taken approximately 0.32 TL according to
2 3,344 1,070 1,770 1.65 average value of day, peak and night time (All
3a 3,378 1,081 2,549 2.35 taxes are included to this price). Lamp cost is
3b 315 100 360 3.6 50 TL including all taxes.
4 48,924 15,656 16,320 1.04
Feasible Calculations:
73,577 23,545 21,639
projects Total = 16x250/1,000x24x360x1.1
consumption of
is a small part of total lamp number. For example, 250 W mercury
in the air conditioner center, 16-pcs 250W mercury lamp
lamps were used. Conventional fluorescent lamps = 38,016 kW
Total = 16x45/1,000x24x360x1.08
can be changed with CFL or LED lamps for saving consumption of
energy. 45 W CFL
= 6,718
 Replacement mercury lamps with the CFL Saving kWh in a = 38,016-6,718
and LED: During this research period, 250 W year
mercury lamps in the air conditioner center of = 31,298 kWh
Emergency Unit were replaced with 45 W compact Saving TL = Saving kWh x Electricity Unit
fluorescent lamps. Same electrical socket can be in a year Price

46 Ç.Ü.Müh.Mim.Fak.Dergisi, 30(1), Haziran 2015

 Ahmet TEKE, Oğuzhan TİMUR, Kasım ZOR

Table 10. The implemented project for interior lighting system

period (year)
consumption

Savings/year

Savings/year
Investment
# of lamps

hours/day

kWh/year
days/year

cost (TL)
Unit cost

Payback
Energy

(kWh)
(TL)

(TL)
Lamp type

250 W mercury lamp 275 W 16 24 360 38,016 - - - - -

45 W CFL 48.6 W 16 24 360 6,718 50 800 31,298 9,389 0.09

= 31,298 * 0.3 TL = 10,015 TL. Medium quality electronic ballast price in market
Payback = Total Installed Cost / Total is approximately 7 TL (All taxes are included to
time (year) Saving TL. this price). 18W and 36 W electronic ballast prices
= (Lamp Cost x # of Lamp) / are almost same.
Total Saving TL.
As shown in Table 11 and Table 12, payback
= (50x16) / 10,015 = 0.08 year period is more than 1 year. Otherwise, the
Payback = 0.08 x 12 = 0.95 month demounting of old lamp and mounting of the new
time lamps are difficult and taken a long time. Because
(month) of this, this replacement operation is not feasible
for the hospital. When a new building is installing
 Replacement of 18W conventional or old buildings are reconstructing, electronic
fluorescent lamps by fluorescent lamp with ballast can be preferred instead of magnetic ballast.
electronic ballast in interior lighting systems:
Because interior lighting system has large installed  Replacement 18W conventional fluorescent
capacity and serves wide range of areas, local lamps with 7.5 W fluorescent LED lamps:
applications are more suitable. The values which 7.5 W fluorescent LED lamps can be used instead
are calculated at local area can be generalized for of 18 W conventional fluorescent lamps.
total areas. According to previous mentioned losses and
prices, payback period and other saving values are
Archive, radiation oncology and nuclear medicine calculated as shown in Table 13. When a new
building are taken as example areas. There are 92- installation or restoration, LED lamps are preferred
pcs 4x18W armatures in the nuclear medicine instead of fluorescent lamps electromagnetic
building, 5-pcs 2x18W armatures in the archive ballast. LED lamps are more feasible than the FLs
building and 97-pcs 4x18W armatures in the with electronic ballast.
radiation oncology building. In addition, there are
24 pcs 2x36 W armatures in nuclear medicine, When the lamps of these three building are
152-pcs 2x36W armatures in archive and 25-pcs examined for generalization, kWh per m2 can be
2x36 W armatures in the radiation oncology. Total calculated as shown in Table 14. By using
number of 18 W lamps is 766-pcs and total kWh/m2, energy saving values and saved money as
number of 36 W fluorescent lamps is 402-pcs. The TL are calculated for all area of the hospital. Total
working time of this buildings are between 08:00 area of University Hospital is 128,536 m2 closed
and 17:00 in a day. The unit electricity cost is 0.32 area. Total installed capacity of all hospital for
TL for this period (All taxes are included). While interior lighting can be found 128,536 x 9,73 =
the conventional fluorescent lamps are converted 1,250,655.28 W = 1251 kW. If all the lamps are
to fluorescent lamps with electronic ballast for considered as 18 W fluorescent lamps, the total
18W system, it is enough to change only ballasts. capacity of 69,481-pcs 18 W conventional

Ç.Ü.Müh.Mim.Fak.Dergisi, 30(1), Haziran 2015 47

Calculating Payback Periods for Energy Efficiency Improvement Applications at a University Hospital

Table 11. The planned project_1 for interior lighting system

Investment cost

Payback period
Unit cost (TL)
consumption

Savings/year

Savings/year
# of lamps

hours/day

kWh/year
days/year
Energy

(kWh)

(year)
(TL)

(TL)
Lamp type

250 W mercury lamp 275 W 16 24 360 38,016 - - - - -

45 W CFL 48.6 W 16 24 360 6,718 50 800 31,298 9,389 0.09

Table 12. The planned project_2 for interior lighting system

Energy consumption

Savings/year (kWh)

Savings/year (TL)
Investment cost

Payback period
Unit cost (TL)
# of lamps

hours/day

kWh/year
days/year

(year)
(TL)
Lamp type

36 W conventional FL
46.8W 402 9 360 60,956 - - - - -
with magnetic ballast
36 W FL with electronic
ballast 38.8W 402 9 360 50,536 7 2,814 10,420 3,334 0.85

Table 13. The planned project_3 for interior lighting system

Savings/year (TL)
Investment cost

Payback period
Unit cost (TL)
consumption

Savings/year
# of lamps

hours/day

kWh/year
days/year
Energy

(kWh)

(year)
(TL)

Lamp type

18W conventional FL
23.4W 766 9 360 58,075 - - - - -
with magnetic ballast
7.5 W FL LED 7.95W 766 9 360 19,731 35.4 27,116 38,344 12,270 2.2

Table 14. The calculation of unit W per square meter (W/m2)

Building Installed lamp capacity (W) Total areas (m2)

Nuclear Medicine Building 8,352 1,200

Archive 11,124 1,135

Radiation Oncology 8,784 570

Total 28,260 2,905

Unit W per square meter (W/m2) 9.73

48 Ç.Ü.Müh.Mim.Fak.Dergisi, 30(1), Haziran 2015

 Ahmet TEKE, Oğuzhan TİMUR, Kasım ZOR

fluorescent lamps are calculated easily. If 4-lamp in the hospital. The practical measurement of
fixture with 18 W FL is used, 17,370-pcs 4-lamp 30 kW aspirator motor in the kitchen is shown in
fixture can be calculated. As shown in Table 15, Table 19. Reducing the speed of the motor 15% of
installed cost of LED system is 2,459,627 TL its nominal speed, 36% of energy saving can be
which is very expensive. Because of this reason provided by VSD.
and limited numbers of technical personnel, LED
lamps are preferred instead of conventional 2.2.1. Energy Saving with VSD
fluorescent lamps when the new installation or
restoration. Local areas can be designed by LED The total capacity of motors in the hospital greater
step by step. than 5.5 kW is given in Table 20. In practice, it is
very difficult to use VSDs in condenser and chiller
Table 15. Energy saving potentials for motors. All elevator motors have VSDs. Other
replacement of all 18 W FL lamps motors operate at 60-70% of loading factor. The
18W FL total capacity of motors which can be controlled by
with VSDs is 7,829.7 kW. The compressor motors in
18 W electronic chiller groups, cooling tower fan motors operate
7.5W
Lamp type conv. FL
LED FL
ballast nearly 120 days in a year and ventilator motors and
ballast (ballasts aspirator motors operate nearly 240 days in a year.
are Other motors operate nearly 360 days in a year.
changed) The average loading factor of the motors is nearly
Energy 60% of full load capacity.
consumption 23.4 W 7.95 W 19.4
(W)
Planned Project_1 is energy saving with VSD.
# of lamps 69,481 69,481 69,481
The annual electrical energy consumption of these
Hours/day 9 9 9
motors is nearly 15,495,667 kWh. The estimated
Days/year 360 360 360 energy saving potential by using VSDs is 22% of
kWh 5,267,771 1,789,692 4,367,297 total capacity which equals to 3,409,046 kWh.
Unit cost This saving equals to 1,022,714 TL/year. The total
- 35.4 7
(TL) estimated investment for this project is nearly
Total cost 930,636 TL. The payback period is approximately
- 2,459,627 486,367
(TL)
0.91 years. All motors in Table 20 are suitable for
Savings/year
(kWh)
- 3,478,079 900,474 the VSD control. Some motors such as chiller and
Savings/year conderser motors are different mechanical
- 1,112,985 288,151 structures but they have same features as a simple
(TL)
Payback asynchronous motor. The most important point to
- 2.2 years 1.68 years take into consideration is required capacity.
period (year)

When the motor runs at maximum capacity and

In Table 17, all projects for interior lighting are
this condition is not enough for comfort quality,
compared with each others and the most feasible
there will be no need a VSD device. At the all
project is project 4 with occupancy sensors. The
other conditions, VSD should be used for energy
total investment and energy saving potential for
efficiency.
exterior and interior lighting are summarized in
Table 18.
2.2.2. New Purchase of Energy Efficient Motor
2.2. Implemented and Suggested Projects on
the Electrical Motors and VSDs The numbers of motors (except elevator,
condenser and chiller motors) greater than 5.5 kW
There is a few aspirator motor controlled by VSD is 234. The total capacity of these motors in the
hospital is 7,829.7 kW. These motors are IE1 type

Ç.Ü.Müh.Mim.Fak.Dergisi, 30(1), Haziran 2015 49

Calculating Payback Periods for Energy Efficiency Improvement Applications at a University Hospital

Table 16. The planned project_4 for interior lighting system

Payback period (year)

savings (30%) (kWh)

Investment cost (TL)

Energy consumption
Total area of suitable

Estimated energy

Estimated energy

Unit cost (TL)

savings (TL)
corridors

(kWh)

7,500 m2 326,825 98,047 29,414 16.5 12,375 0.42

Table 17. Feasible projects for interior lighting

Project number Energy saving Energy saving Investment Payback period
kWh/year (TL) (TL) (year)

1 10,672 3,400 5,362 1.6

2 10,420 3,334 2,814 0.85
3 38,344 12,270 27,116 2.2
4 98,047 29,414 12,375 0.42
Feasible projects 98,047 29,414 12,375 0.42

Table 18. Energy saving potentials for overall lighting system

Lighting System Energy saving Energy Saving Investment
kWh/year (TL) (TL)

Feasible projects for interior lighting 98,047 29,414 12,375

Feasible projects for exterior lighting 73,577 23,545 21,639
TOTAL 171,624 52,959 34,014

Table 19. Measurement results of 30 kW aspirator motor in the kitchen

30 kW Aspirator Motor in kitchen

Phase R S T
Without
VSD

Power (kW) 8 7.8 7.9

Current (A) 40 37 40
Phase R S T
With VSD

Power (kW) 4.9 5.2 5.1

Current (A) 23 24 23

50 Ç.Ü.Müh.Mim.Fak.Dergisi, 30(1), Haziran 2015

 Ahmet TEKE, Oğuzhan TİMUR, Kasım ZOR

Table 20. Existing motors greater than 5.5 kW

Motor Types Total Capacity (kW)
HVAC motors Compressor 6,196.5
Condenser 582
Chiller 875
Cooling tower fan motor 327
Ventilator 806.4
Aspirator 260.3
Other motors Boosters 142
Elevators 219.7
Compressors 97.5

Table 21. The planned project_2 for electrical motor and VSD systems
Motor type Energy consumption Energy saving Energy Investment
kWh/year kWh/year saving (TL) (TL)

Existing motors 15,495,667 - - -

New IE3 motors 15,077,284 418,383 125,514 672,345

Table 22. Energy saving potentials for overall motor and VSD systems

Investment
Motor system Saving kWh/year Saving (TL)
(TL)

Project 1: with VSD 3,409,046 1,022,714 930,636

Project 2: purchase of energy efficient motor 418,383 125,514 672,345

TOTAL 3,827,283 1,148,184 1,602,981

and operate nearly at 60-70% of loading factor. If MW was chosen for payback analyzes of both
these motors are replaced by IE3 type motors, the cogeneration and trigeneration plants. For this
efficiency of the overall system can be increased rating, cogeneration plant with a steam boiler has
2.7% existing efficiency as shown in Table 21. The an investment cost of 1,400,000 $, annual revenue
total investment for this project is 672,345 TL. of 928,135 $ and calculated payback time of the
Energy saving TL is 125,514. As a result, payback investment is 1.51 years. For trigeneration plant
period can be calculated as 5.36 years which is not with double-effect absorption chiller, system cost
feasible for the hospital. Energy saving potentials is 2,050,000 $, annual revenue of the system is
for overall motor and VSD systems are shown in 900,405 $ and payback time of the system cost is
Table 22. Bold color project is feasible for the 2.27 years [14]. Other implemented and suggested
hospital. projects on the HVAC systems are presented in
below sub-sections.
2.3. Implemented and Suggested Projects on
the HVAC Systems 2.3.1. Heat Saving
As calculated in [14], a capacity rating of 2.145 The total capacity of motors in the hospital greater

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Calculating Payback Periods for Energy Efficiency Improvement Applications at a University Hospital

than 5.5 kW is given in Table 20. In practice, it is escape and outside air from entering. Arranging
very difficult to use VSDs in condenser and chiller the non-automatic and always left open outer doors
motors. All elevator motors have VSDs. Other as automatic doors with air curtains will be useful
motors operate at 60-70% of loading factor. The to keep conditioned air inside the building. The
total capacity of motors which can be controlled by approximate cost of an automatic doors and its air
VSDs is 7,829.7 kW. Steam leaks consist because curtain is around maximum 7,000 TL. The
of inadequacy insulation of heat center. For fuel polyclinic parts of ground floor exits and the both
saving and obtaining efficiency at desired values, of exits which are between morgue-kitchen need to
the steam lines should be renewed and its be reorganized.
insulation should be performed. However, for
renew of this line, galleries should be also  Use of Chemicals in Heating and Cooling
renewed. In galleries there is no enough space for Systems: Energy saving can be satisfied with the
these renewal processes. use of chemicals which make the transfer of heat
without loss by preventing calcification in all
Automatic blow-down system and degasser insulation for heating and cooling system (1 mm
devices are required on the steam boilers which are calcification in the installation causes
used in the heat centers. These changes should be approximately 1-2% energy loss). Total energy
performed on boilers in heat center while transition consumption of the University Hospital for last 12
to natural gas. This point was reported to the months is 4,749.40 TOE (23,960,320 kWh
Department of Construction and Technical Works. electrical energy (2,060.58 TOE) and 2,727 tonnes
fuel oil (2,688.82 TOE)). Annual estimated gain
In university hospital building the existing heat from this investment is 47.49 TOE.
exchangers should be replaced with plate heat The lifetime of installations will be longer and
exchangers when they are broken or out of run. All getting resistance against corrosion and abrasion
pipes in hospital air conditioning room are will be satisfied.
required to be renewed by checking their Its annual cost is 40,000 TL.
insulations for the purpose of heat leakages. The
valves existing in heat center and air conditioning  Valve insulation jacket application: Due to
room should be insulated. non-isolated control devices (steam traps, check
Thermostatic valves should be used on radiators valves, etc.) used in heating and cooling systems,
because the polyclinic blocks are heated by energy losses occur in the heat center and hospital.
radiator system. The old pipelines of central For example, heat loss of a 40 mm steam valve is
heating system should be renewed and radiators measured as 1,344 kcal/h without insulation and
should be replaced by the efficient ones. But, if 166 kcal/h with insulation using the heat thermal
renovating of polyclinic will be performed, this imaging cameras. The loss difference is
system should be completely removed and central 1,178 kcal/h. The annual saving from these control
air conditioning system Variable Refrigerant devices is approximately 10,177,920 kcal. There
Volume-Variable Refrigerant Flow (VRV-VRF) are 1,250 numbers of control devices with different
should be applied and fresh air heat recovery diameters in the hospital. To minimize this losses,
devices should be designed. The elimination of as a result of providing insulation with heat-
radiators will satisfy fuel-oil saving. insulating jacket of control elements of the
installation. A sample of measurements is shown
The fuel system in heat center will be changed to in Figure 1 and Figure 2.
natural gas system because of that there is no need
for investment in improvement of fuel currently. 10,177,920 kcal×1250-pcs=1,272,240,000 kcal
can be saved. (127.22 TOE)
 Air Curtains: Air curtains should be placed on Financial gain of this insulation is approximately
the doors opening to the outside in the hospital. 1,272,240,000 kcal / 1,785 = 712,739,000 kg
This will prevent the inside conditioned air to steam × 0.121TL = 862,414TL/year.

52 Ç.Ü.Müh.Mim.Fak.Dergisi, 30(1), Haziran 2015

 Ahmet TEKE, Oğuzhan TİMUR, Kasım ZOR

Heating and cooling process continue for an these air conditioners are accepted to operate on
average 8 months in a year. In this case, the annual average 8 hours per day they will consume energy
saving is 862,414× (8/12) = 574,942TL/year. 264 days of a year from 22 work days per month.
From here, the annual energy consumption per day
The insulation cost of 1,250 control devices is is calculated as 9,559.2kW × 264 day =
approximately 90,000 TL. The investment pays for 2,444,428.8 kWh annual consumption. Its cost is
itself in 2-3 months. The lifetime of thermal 733,328.64TL/year.
insulation material is considered as 5-10 years.
[15] shows that the energy saving rate of air
conditioning in hall is 19.7–49.3%. Similarly at
[16] and its investigated studies show that, VRV
system improves the energy efficiency and reduces
cooling energy consumption for part load
conditions lower than 50%. Because of this and
similar situation, after installing to inverter system
(central air-conditioning system or VRV system
can be) average saving will be 40% generally.
2,444,428.8kW×0.40=977,771.52kWh×0.32TL
Figure 1. Steam valves with/without valve jacket
=312,886.88 TL annual savings would be
achieved. Approximately 1,450,000TL investment
is required for the all air conditioners. The
investment will pay for itself over 4.63 years
which is not feasible for the hospital.

 Central Air Conditioners: The burn unit,

emergency, intermediate intensive care units
(neurology, cardiovascular, newborn 2), Floors 2-
3-4, centrals of floors 1-4-5-6 (heating and
Figure 2. The measurement of the steam valves cooling) have inverter system. Some of other air
with thermal camera conditioner centrals of hospital have to be changed
by the air conditioner centrals which are new
2.3.2. Cooling Systems generation and with automation system,
meanwhile centrals are being changed hygienic
 Split Air Conditioners: The energy classes of centrals have to be designed for required places.
split air conditioners at polyclinic blocks are As a result, energy saving potentials for overall
generally C or D. electric energy savings will be HVAC systems and feasible project are
provided with the installation of central air summarized in Table 23. The projects with bold
conditioning system by eliminating the current color are feasible.
split air conditioners. This structuring will be
useful and long term system by preventing 2.4. Implemented and Suggested Projects for
environmental pollution and also providing inside Other Systems
desired ergonomic values. All 777-pcs of split air
conditioners used in the hospital are classes C or Exterior Wall Insulation and Covering:
D. These air conditioners consume 20-30% more
energy than class A. If the air conditioners have Regulation on increasing efficiency for energy
inverter system energy saving will be 20-40%. Air resources and in the use of energy was published
conditioners should be chosen A+++ energy class on 25.10.2008 and energy performance of building
or inverter system from now. The total installed regulation was published on 05.12.2008. Energy
capacity of air conditioners is 1,157.4 kWh. If efficiency strategy paper of 2012-2023 was

Ç.Ü.Müh.Mim.Fak.Dergisi, 30(1), Haziran 2015 53

Calculating Payback Periods for Energy Efficiency Improvement Applications at a University Hospital

Table 23. Energy saving potentials for overall HVAC systems

Total
Saving electricity Saving others Saving Investment
HVAC System savings
kWh / year (TOE) TOE
TOE
(TL) (TL)

Valve insulation jacket

- 127.22 127.22 574,942 90,000
application
Use of chemicals 47.49 47.49 95,145 40,000
Installation of VRV systems 977,771.52
- 84.09 312,886.88 1,450,000
instead of split AC system (84.09)

published on 25.02.2012 by the high planning saving and comfortable room temperature.
council and measures were taken to improve the However, the coating is required to protect heat
efficiency which were planned to perform until insulation materials from damage. This process
2023. According to regulation with law number will eliminate the cost of painting and maintenance
27035 related with increasing efficiency for energy of the facades and will be used without any
resources and in the use of energy, the public operation to exterior facade as the lifetime of the
section buildings which have total construction used coating material. The paint and plaster on the
area at least 10,000m2 or the total annual energy exterior facade are blistering and the rips occurred
consumption is greater or equal to 250 TEP in the rainy weather over time when expose to sun
(tonnes of oil equivalent) have to employ an and rain can be totally prevented. 26-48% of the
energy manager or take the service of energy heat lost from a building is sourced from windows.
management (250 TOE equals to 2,907,500 kWh). Changing all used glasses with double glazing
Total annual electric energy consumption of our glasses or with drawling of double-sided film to
hospital in 2012 was 21,303,600.00 kWh. It is glasses will save most of the energy. This process
estimated that the total consumption will be will prevent both the escape of heat such and the
25,000,000.00 kWh with the new plants, loads and entering inside of cold or warm air. The insulation
transformer putting into use in 2013. The of the rooftop and basement of the building should
regulation of energy performance on buildings be performed.
published in the official gazette no 27075 on
05.12.2008 legally obliges to take Energy Total external facade: 35,000m2
Performance Certificate (EKB) for the existing The cost of insulation and jacketing: 150 TL/m2
buildings which are new and with a floor area Total investment cost (approximately):
greater than 1,000m2. 5,250,000 TL

Energy performance certificate have to be arranged The total annual energy cost of hospital last 12
for the existing buildings and for buildings under months is approximately 12,000,000 TL
construction and not yet received permission to use (5,000,000 TL (price of electricity without lighting
the building in ten years from the date of and other equipment expenditures) + 7,000,000 TL
publication of the Law on Energy Efficiency fuel-oil). If minimum 30% of consumed energy is
(before 02.05.2017). saved only from exterior insulation and jacketing;
Energy consumed for cooling 3 MVA during 4
It is required to perform insulation and jacketing to months (instantaneous consumption). Saving
facade of our buildings until the date 02.05.2017 potential for electricity consumption is
according to the related regulations. Insulation will 5,000,000×0.32=1,600,000×4/12=533,333.00 TL.
provide to reach the desired heat inside fast and Annual fuel-oil consumption in stokehole is
minimize losses so it will prevent to operate 7,000,000 TL. 80% of fuel-oil consumption is used
motors of heating or cooling systems at full for heating. Saving from there will be
capacity. At the same time it will provide the fuel- 7,000,000×0.80×0.32= 1,792,000 TL.

54 Ç.Ü.Müh.Mim.Fak.Dergisi, 30(1), Haziran 2015

 Ahmet TEKE, Oğuzhan TİMUR, Kasım ZOR

Most of the energy cost is related with heating and specification for MV/LV distribution power
cooling (fuel-oil and electric energy). In addition transformers, a standard 1000 kVA step-down
the cost of painting for every 5 years will be transformer has 10.5 kW load losses and 2 kW no-
eliminated with the exterior painting of the load losses. Type-A 1000 kVA step-down
building. Annul saving from the exterior painting transformer has 8.9 kW load losses and 1.45 kW
will be approximately 250,000 TL. In this case, the no-load losses. Type-A 1000 kVA high efficiency
total savings become 1,792,000 + transformer consumes 2.15 kW less energy than a
533,333+250,000= 2,575,333 TL. The total standard 1000 kVA transformer. The annual loss
investment is considered as 5,250,000.Investment difference can be calculated as 2.15x24x360=
will take to pay for itself in 2.03 years 18,576 kWh. In Turkey, the unit price of electricity
(5,250,000/2,575,333). Because the total is a 0.16$ (All taxes are included to this price).
installation cost of this project is very high, this Annual saving is 2,973 $. The purchase price of
project is not easy to implement. Type-A 1000 kVA transformer is 2,400$ more
expensive than a standard one. The payback period
 Personals and end Users’ Education: It is of this investment is nearly 10 months.
important to keep windows and doors closed for
cooling and heating. The lamps that are not needed 3. CONCLUSIONS
to operate should be turned off. Personal should
turn off the electrical devices which are not needed In this research paper, the best energy saving
except drug box, refrigerator etc. at the end of the approaches and energy efficiency improvement
working hours. Especially split air conditioners, methods for University Hospital giving the
computers and printers should be closed. At only payback periods of the suggestions were
the Hospital Information and Management System developed. Approximately up to 10% energy
Department, more than 800 computers and 500 saving without any charges can be achieved by
printers have been used approximately. Even if a using simple precautions. The findings of this
device consumes electricity one thousandth of research study help the engineers and managers in
normal consumption, when considering the total the hospitals for reducing energy consumption
number of devices, their effect will be large. while maintaining the quality of service.
This paper proves that applying the energy
 UPS Efficiency: New technology 3-level (3-L) efficiency and saving practices will save
UPSs of ENEL Company are 6% more efficient considerable amounts in the electrical bills and
than traditional transformer based UPSs for 100% fuel. In this paper, new energy consumption rates
of full load capacity. The efficiency difference is by suggesting energy improvement applications
10% for 50% of full load capacity. For example, and energy saving methods are compared with the
100 kVA 3-L UPS saves $8,760 (50,265 kWh) a present energy consumption rates in the hospital.
year in electricity costs than transformer based As a result of the detailed analysis on the existing
UPS. The payback period for this replacement is system, 20-40% of energy saving potential is
approximately 2 or 3 years. At the hospital, all estimated at the University Hospital.
UPSs are transformer based type. The loading
capacity of the UPSs is approximately 25%. 4. ACKNOWLEDGEMENTS

The authors greatly appreciate the financial

The efficiency difference for this loading factor is support of Scientific Research Project Unit of
approximately 10%. The total capacity of UPSs is Çukurova University.
2,030 kVA. The energy saving for this - Project title/number: Energy management in
replacement is nearly kWh. Çukurova University, MMF2013YL8.
(2030/4) ×0.1×0.32×24×360= 140,313 kWh. - Project title/number: Developing a software
program to determine the optimal capacity rating
 Transformer Losses: According to technical of cogeneration and trigeneration plants driven by

Ç.Ü.Müh.Mim.Fak.Dergisi, 30(1), Haziran 2015 55

 Calculating Payback Periods for Energy Efficiency Improvement Applications at a University Hospital

gas engines for unlicensed generation of HVAC Systems Considering Economic and
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56 Ç.Ü.Müh.Mim.Fak.Dergisi, 30(1), Haziran 2015

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