1
Presentation of measures in
energy audits
- Example
EFFECT4buildings Toolbox:
Financial calculations; Annex 3
2
EFFECT4buildings project is implemented with the support from the EU funding Programme Interreg Baltic Sea
Region (European Regional Development Fund) and Norwegian national funding. The aim of the project is to
improve the capacity of public building managers in the Baltic Sea Region by providing them a comprehensive
decision-making support toolbox with a set of financial instruments to unlock the investments and lower the risks
of implementing energy efficiency measures in buildings owned by public stakeholders. More information:
http://www.effect4buildings.se/
Partners
The project “Effective Financing Tools for implementing Energy Efficiency in Buildings” (EFFECT4buildings)
develops in collaboration with public building managers a comprehensive decision-making support toolbox
with a set of financial instruments: Financial calculation tools; Bundling; Funding; Convincing decision
makers; Energy Performance Contract; Multi Service Contract; Green Lease Contract; Prosumerism. The
tools and instruments chosen by the project has the biggest potential to help building managers to
overcome financial barriers, based on nearly 40 interviews with the target group. The project improves
these tools through different real cases.
To make sure building managers invest in the best available solutions, more knowledge on different
possibilities is needed as well as confirmation from colleagues that the solutions performs well.
EFFECT4buildings mapped technological solutions for energy efficiency in buildings with the aim to share
knowledge and experiences of energy efficiency solutions among building managers in the Baltic Sea Region.
This document includes a new standard template for presenting proposal of measures based on conducted
energy audit. The template can be introduced and connect as a part of Total Concept Method process by
presenting the package of proposed measures with the TotalTool. Furthermore, the template can be utilized
in a comprehensive way as a separate excel sheet by including provided results to any calculation method
published in this toolbox. Optionally template will also provide advantage to any other appropriate energy
audit report and increase the implementation of energy efficiency measures.
3
Example of presentation of measures in
energy audits
Summary
The following report contains the result of an energy audit and proposals regarding how the
energy use and the energy costs can be decreased for XXXX.
XXXX is producing cement enclosures for fireplaces and stoves. The production plant, in this
report is located in XXXXX. XXXX also has another site, west of XXXXX. This site is treated in a
separate report.
At XXXX, elements of light versions of concrete is produced. The elements are used in fireplaces
and stoves to store heat. Another product is Marble which is cut into smaller pieces.
XXXX production site XXXX use electricity, natural gas and diesel as types of energy. During the
twelve months’ period from 2015-08-01 to 2016-07-31 the total energy use was 2 799 922
kWh and the total costs associated with energy use was € 138 306.
Table 1 shows a summary of the quantified measures in this report.
4
Process
Measure
Savings
Investment
cost [€]
Payback
time
[year]
Net
present
value
[€]
Internal
rate of
return
[kWh/year]
[€/year]
Building
Building 6: Apply an extra
insulated glass unit on
specified windows and
decrease the transmission
losses.
14 800
n.gas
550
4 000
7,3
1 000
11 %
Building
Building 7: Construct a well-
insulated wall that replaces
specified windows and
decrease the transmission
losses.
26 800
n.gas
990
7 200
7,3
3 000
12 %
Building
Building 7: Repair broken
window and decrease the
transmission losses.
3 500
n.gas
130
260
2,0
1 000
50 %
Building
Seal industrial doors in Building
2 and 7.
42 000
n.gas
1 550
500
0,3
10 000
310 %
Lighting
Converting from T8
fluorescent tubes to T5 in
production areas, building 3
and 12.
51 400
el
4 900
14 410
2,9
18 000
32 %
Lighting
Converting from T8
fluorescent tubes to LED tubes
and ECO/ES in specified
premises.
42 200
el
4 250
15 560
3,7
13 000
24 %
Ventilation
Sand blasting: equip fan motor
with a variable frequency
drive, VFD.
25 000
el
2 200
5 000
2,3
10 000
43 %
Compressed
air
Invest and install a compressor
with variable speed and use
this as the main compressor.
60 000
el
5 300
8 900
1,7
27 000
59 %
Compressed
air
Kaeser ASD 37 T: recover heat
to building 3 and fix current air
transportation.
1 500
el
70 000
n.gas
2 700
3 000
1,1
15 000
90 %
5
Compressed
air
Kaeser Airtower 19: recover
heat to building 12 and replace
filter more regularly.
14 000
n.gas
550
2 000
3,6
2 000
24 %
Production
Furnaces, building 12: Keep
gas-fired furnaces instead of
switching to electricity.
Recover heat from the
furnaces through a heat
exchanger, without
transferring CO
2
to premises
where people work.
Not quant.
----
Not quant.
----
----
----
Table 1: Shows a summary of the quantified measures in this report.
Table 22: Total concept method, by BELOK. Summary of the quantified measures in this report
presented with a graph to show return of investment. Y-axis showing yearly savings in SEK/year
and X-axel showing cost of energy investment in SEK.
6
Table of Contents
Summary 3
1 Introduction 7
1.1 Aim 7
1.2 Method 7
1.3 Boundaries 9
1.4 Assumptions 9
2 Description of the company 10
2.1 Contact details 10
2.2 Buildings 11
3 Energy statistics 15
3.1 Electricity 15
3.2 Natural gas 15
3.3 Diesel 17
4 Situation analysis and proposals 18
4.1 Lighting 20
4.2 Ventilation 23
4.3 Compressed air 24
4.4 Space heating and domestic hot water 28
4.5 Production 29
Appendices 30
Overview of site 30
Lighting survey 31
Calculations 34
Measurements 39
7
Introduction
Costs, related to energy are a major part of most manufacturing companies’ total costs. Due
to the fast growth of some large countries and the fact that it is becoming more difficult to
increase the oil production and also the extraction of other natural resources, the price of
many different types of energy has increased. It is therefore important for companies to start
working with questions regarding energy consumption and to manufacture in a way that is
energy efficient.
Another reason for reducing the energy consumption is the environmental problems that the
world is facing. Reduced energy consumption usually means a reduced environmental impact.
Aim
The aim is to perform an energy audit of the company’s energy use and to identify any
proposals for actions to reduce the energy costs. The audit is essential in order to find any
proposals for action and it also has an intrinsic value as it shows how the energy is distributed
among the various support- and production processes.
Method
The total energy consumption of the company has been studied. The energy statistics shows
how much electricity and thermal energy the company is using during a year and how the
energy use is distributed over time. Thereafter measurements have been performed and
different data have been collected in order to understand how the power and energy use is
distributed among different processes. The operation times have been obtained both by
measurements and by discussions with operating personnel.
Measuring instruments with data logging function, shown in Figure 1, measures the current
over time and then by using numerical integration the electrical power and the energy use can
be determined. The time duration of the measurements has been about a week so that both
the weekdays and the weekend are represented. Finally, the measurements have been
analysed in order to find proposals for action regarding possibilities to reduce the energy costs.
8
Figure 1: The picture to the left shows two installed measuring instruments with logging
function. The picture to the right shows the result of the measurement as a graph where the
power use is plotted against the time.
9
Boundaries
• For this energy audit, the production site XXXX premises and associated activities, are
used as boundaries. XXXX also has a production site on the other side of XXXX. This site
is treated in a separate report.
• To make the energy audits easier to read and understand all transports between the
production sites in XXXX and other external transports is included in this energy audit,
of the production site XXXX.
• This energy audit has been performed during the period XXXX.
• This report and the work performed in this energy audit, following these standards:
o EN 16247-1, General requirements
o EN 16247-3, Processes
o EN 16247-5, Competence of energy auditors
• In order to include all support and production processes, the measures are demarcated
to provide a good base for investment. The proposals should not be interpreted to be
anywhere close to technical design. In case that the calculations for the proposed
technical measures include design parameters, such as number of light fixtures in case
of alternative lighting or installed capacity for alternative heating sources, the used
numbers shall be considered as approximate numbers and the proposals be considered
as a part of a pre-design study. The reason that we show our calculations, in appendices,
are to clarify how the base for the proposed investment has been developed and also
as a tool for the company to check the credibility of the proposals. The calculations can
also be used in final evaluation of the proposals. We recommend the technical design
of the proposed measures to be made by an authorised design firm.
Assumptions
• In normal cases the measurements, although performed during normally just one week,
are assumed to be representative for the full year.
• The savings calculated for the proposed measures are not related to each other. It
means that the savings is presented as if just the single, current proposal was
implemented. This could be changed if many proposals, which interact with each other,
were implemented.
• The presented investment costs for the proposed measures are based upon
experiences from previous implementation at other industrial sites. In situations where
e.g. large pipe systems are proposed to be installed it may be difficult to correctly
predict the investment costs since the final design will determine quantities etc. In
order to make the final evaluation of the proposed measures the company is
recommended to request sharp offers from a number of potential suppliers.
• LCC calculations are based on a nominal interest rate of 10 % and a nominal annual
energy cost increase of 2 %.
10
Description of the company
XXXX is producing cement enclosures for fireplaces and stoves. The production plant, in this
report called XXXX, is located in XXXX. XXXX also has another site, west of XXXX. This site is
treated in a separate report.
At XXXX, elements of light versions of concrete is produced. The elements are used in fireplaces
and stoves to store heat. Another product is Marble which is cut into smaller pieces.
The support processes which consumes most energy is space heating, lighting and compressed
air. In the production the largest energy consumer is thermal treatment.
The number of employees at XXXX is 170. The normal working hours in production is 1 shift
between 06.00 am and 02.00 pm. Two of seven divisions are also working 2 and 3 shifts.
Sometimes there is production on Saturdays, which was the case during the week of
measurements.
The working hours at the office is between 08.00 am and 04.00 pm. The production is normally
closed for holidays during four weeks per year, of which two weeks are during the summer.
XXXX is certified in both ISO 9001 and ISO 14001 and is working with questions regarding
energy consumption. This report should be used as guideline of how the energy is used today
and how it could be used more effectively.
Contact details
Company:
Address:
Phone:
Contact person:
Phone:
Email:
Energy analyst: Peter Karlsson
Phone: +46 708281151
Energy analyst: Mattias Jonsson
Phone: +46 738406038
Energy analyst: Curt Björk
Phone: +46 737096008
11
Buildings
The site consists of several buildings as shown in Figure 4 in appendices. The total area of all
buildings is 13 400 m
2
of which the heated area is 11 100 m
2
.
Most buildings are used for production but there is also an office building and a building for
staff where dressing rooms and canteen is located. There are also several unheated tents.
The building envelopes vary but most of them have walls which are plastered and consists of
20 cm concrete with an insulating layer of 10 cm foam. The average U-values for ceilings and
walls of these buildings have been calculated to 0,34 W/m
2
K.
Some building envelopes have obvious defects and these building are the reason why the need
of heating is higher on XXXX compared to XXXX (see separate report). The key-value for heating
is 113 kWh/m
2
(based on period for energy statistics, see chapter 0) compared to 99 kWh/m
2
for XXXX. Measures for these buildings are given in the text below.
Roof, Building 6
During our visit we noticed that a crew of construction workers were in operation on the roof
of building 6, replacing/repairing the tar roof layer.
Unfortunately, nothing more was done; Building 6 has a building envelope that is in miserable
condition and annual heating costs must be soaring. It would therefore have been a golden
opportunity to add at least 10 cm of insulation on the existing roof at the time that the crew
worked on the roof. There would of course be an additional investment cost associated to the
insulation but it would be a marginal cost, adding some value in terms of energy savings instead
of only keeping the roof waterproof.
Our recommendation to the management is to evaluate this marginal investment the next time
that a bad roof will be repaired and the work crew is already in place. We can help you in
calculating the energy savings when such an evaluation will be done.
Measure, apply an extra insulated glass unit on the windows in Building 6.
Saving
Natural gas:
14 800
kWh/year
Cost reduction
550 €/year
Costs
Investment cost:
€ 4 000
Financial calculations
Payback:
7,3 years
LCC (cost saving 15 years):
€ 710
12
Apply an extra insulated glass unit on the windows in Building 6 and thereby reduce heat losses
through the windows.
A place built insulated glass unit means only about a quarter of the cost compared to the cost
of replacing the entire window. The unit is applied from the inside and therefore does not
affect the building’s appearance. The windows U-values are considered to be reduced from 6
W/m²K to 1,3 W/m²K.
In addition to energy savings the measure also reduces cold drafts in the winter and therefore
contributes to a better working environment.
Measure, construct a well-insulated wall that replaces the windows in Building 7.
One long side of Building 7 consists of two rows of windows
where the windows on the bottom row are insulated glazing (IG)
windows with an estimated U-value of 1,5 W/m
2
K. One of these
windows is broken and should be repaired immediately (see
measure below)
The windows on the upper row are old windows with only one
glass. These windows have an estimated U-value of 5 W/m
2
K and
are considered to be the part of the building which contributes
most to transmission losses, relative to size.
Construct a well-insulated wall that replaces
the one glass windows in Building 7 and
decrease the transmission losses.
The working environment is not expected to
get worse by replacing the windows,
because the IG windows will let daylight in.
It is considered possible to decrease the U-
value from 5 W/m²K to 0,3 W/m²K.
Measure, repair window in Building 7.
Saving
Natural gas:
26 800
kWh/year
Cost reduction
990 €/year
Costs
Investment cost:
€ 7 200
Financial calculations
Payback:
7,3 years
LCC (cost saving 20 years):
€ 2 520
Saving
Natural gas:
3 500 kWh/year
Cost reduction
130 €/year
Costs
Figure 2: Windows on building 7.
14
Measure, seal industrial doors in Buildings 2 and 7.
The industrial doors in Buildings 2 and 7 are
leaking in outside air and should be sealed.
In building 2, three doors are in bad shape
and can be seen in Figure 3
The savings is difficult to calculate but have
been estimated with standard value based
on the size of the area that is leaking.
Saving
Natural gas:
42 000
kWh/year
Cost reduction
1 550 €/year
Costs
Investment cost:
€ 500
Financial calculations
Payback:
0,3 years
LCC (cost saving 10 years):
€ 9 900
Figure 3: Shows industrial doors in Buildings 2 and 7
15
Energy statistics
This chapter presents all purchased energy and the costs associated with energy use broken
down by individual types of energy. All costs are excluding VAT.
XXXX’s production site XXXX use electricity, natural gas and diesel as types of energy. During
the twelve months’ period from 2015-08-01 to 2016-07-31 the total energy use was 2 799 922
kWh and the total costs associated with energy use was € 138 306.
Electricity
The total electricity use during the twelve months’ period from 2015-08-01 to 2016-07-31 was
686 710 kWh
1
according to Chart 1. The cost for electricity during the same period was €
58 522
2
.
The variable cost of electricity, i.e. the cost that depends on the electricity use, amounts to
0,088 €/kWh
3
. The cost depending on the electricity demand amounts to 28,9 €/kW and year
4
.
These are the costs that are used when the savings regarding energy use are calculated to
reduced energy costs, for proposed measures.
Chart 1: Shows the load curve for electricity during the twelve months’ period from 2015-08-01
to 2016-07-31.
Unit
Name
Avr
Min
Max
Energy [kWh]
kW
Power
78,18
0,00
247,60
686 710
Natural gas
16
1
XXXX.
2
XXXX.
3
XXXX.
4
XXXX.
17
The total consumption of natural gas during the twelve months’ period from 2015-08-01 to
2016-07-31 was 1 952 786 kWh
5
according to Chart 2. The cost for natural gas during the
same period was € 66 469
6
.
The variable cost of natural gas, i.e. the cost that depends on the use of gas, amounts to 0,037
€/kWh
7
. This is the costs that is used when the savings regarding energy use are calculated to
reduced energy costs, for proposed measures.
Chart 2: Shows the consumption of natural gas for each month during the twelve months’
period from 2015-08-01 to 2016-07-31.
Diesel
The total consumption of diesel during the twelve months’ period from 2015-08-01 to 2016-
07-31 was 160 426 kWh
8
. The cost for diesel during the same period was € 13 315
9
.
The variable cost of diesel, i.e. the cost that depends on the use of diesel, amounts to 0,083
€/kWh
10
. This is the cost that is used when the savings regarding energy use are calculated to
reduced energy costs, for proposed measures.
5
XXXX
6
XXXX
7
XXXX
8
XXXX
9
XXXX
10
XXXX
33508
52085
175517
230875
232916
339316
267761
274398
169715
84272
58851
33572
0
50000
100000
150000
200000
250000
300000
350000
400000
kWh
Natural Gas 2015/2016
18
Situation analysis and proposals
The following chapter describes how the energy is used at present and also presents proposals
on how energy can be used more efficiently. Chart 3 shows how electricity, natural gas and
diesel consumption is distributed among the various support and production processes, which
are described in more detail under the headings below.
Calculations on how the energy is used are based on:
- The performed measurements, shown in the appendices.
- The energy statistics during the twelve months’ period from 2015-08-01 to 2016-07-
31, described in chapter 0.
- The inventory of installed power and capacities.
- Observed operating patterns.
- Identified energy recovery.
19
Chart 3: Energy balance, shows how the energy use is distributed among the various support
and production processes.
20
Lighting
The lighting annually uses approximately 284 600 kWh
el
according to the lighting survey that
can be found in the appendices. The total installed power for the lighting is 96,7 kW.
The majority of all lighting consists of T8 fluorescent tubes 58W and 36W. In building 12 and 6
a few new LED fixtures that replaces the T8 fixtures can be find.
The general lighting is considered to provide a good working environment. The lux value varies
between 150 to 400 lx and is lowest in warehouses and highest in premises with work that
requires better lighting such as mounting.
As a KPI value (Key performance indicator) for lighting, installed power per square meter is
used. The key value does not include how strong the lighting is. I high KPI value can be
explained by great need of lighting. The lux value has therefore been measured.
In Table 3 the KPI and lux value is shown for chosen premises. All of these premises have T8
fluorescent as general lighting and the different in KPI-value is explained by difference in lux-
value and parameters specific for the premises such as ceiling height and colours of walls,
ceiling and floor.
Premises
Installed power [kW]
KPI-value [W/m
2
]
Lux [lx]
Building 2 - Marble
5,4
9,3
250
Building 3 - Fireplaces
22,2
7,9
160
Building 3 - Fireplaces
warehouse
6,8
5
200
Building 7
10,1
13,3
400
Building 10 - Slate 1
4,4
8,9
400
Building 10 - Slate 2
3,1
6,4
350
Building 11 - Warehouse
SL. TH
3,1
3,6
150
Building 12 - Thermotte
12,2
8,3
350
Table 3: Shows KPI value for chosen premises. An overview of buildings and premises are shown
in appendices in Figure 4. Lux values are an average value that represents the entire premises.
Higher and lower Lux value can appear in specific parts of the premises.
Measure, Converting from T8 fluorescent tubes to T5.
Saving
Electricity:
51 400
kWh/year
Cost reduction
4 900 €/year
Costs
Investment cost:
€ 14 410
Financial calculations
21
The premises with highest electricity use
during one year are the production area in
building 3 (fireplaces) and building 12
(Thermotte).
In these premises it is profitable to change from T8 fluorescent tubes. The lighting technology
that is considered to be most suitable is T5 fluorescent tubes with a higher light output per
Watt and a more efficient drive than T8 fluorescent tubes.
The reason that LED is not suggested in these premises is that it would be too high investment
compared to savings. LED tubes are not suggested because most existring fixtures are old and
need to be changed.
Measure, Converting from T8 fluorescent tubes to LED tubes.
Payback:
2,9 years
LCC (cost saving 10 years):
€ 18 470
Saving
Electricity:
42 200
kWh/year
Cost reduction
4 250 €/year
Costs
Investment cost:
€ 15 560
Financial calculations
Payback:
3,7 years
LCC (cost saving 10 years):
€ 12 960
22
In the other premises a combination between changing from T8 fluorescent tubes to LED-tubes
and ECO/ES tubes would be the best alternative. T5 tubes are not profitable here because of
too low run time and too low installed power for current lighting.
Current fixtures are old but are expected to last a few more years. LED technology is moving
forward fast and new fixtures for industrial premises will be cheaper and better in a few years
and therefore keeping current fixtures but changing light source is suggested.
For fixtures with least wear, LED tubes is the best alternative and for the other fixtures ECO/ES
tubes should be applied. Both of these lighting technologies are explained under headings
below. The calculations for these measures have been made with the assumption that half of
the current T8 fluorescent tubes are changed for LED tubes and the half for ECO/ES tubes.
In building 10 personnel are worried that changing light source would mean a cooler light. Both
LED tubes and ECO/ES are available as warmer light down to 3000 K, why this is not an
argument.
LED tubes
Converting from T8 fluorescent tubes to LED tubes which can be applied in existing fixtures
and therefore means a lower investment cost than most other alternatives.
The T8 58W (including drive means 68W) are exchanged for LED 25W (including drive means
30 W) and T8 36W (including drive means 43W) for LED 21W (including drive means 24W). The
power varies slightly between different providers.
LED tubes produce less light than T8 fluorescent tubes but directs all the lights downwards.
Therefore, LED tubes are suitable with existing fittings with poor reflectors that can´t take
advantage of the higher light output of the T8 fluorescent tubes. Before converting all the light
sources, a smaller number of LED tubes should be purchased to ensure that the lighting still
provide a good working environment.
The LED tubes have a higher life expectancy than T8 fluorescent tubes which means that the
tubes don’t have to be replaced so often. The maintenance cost is thereby reduced.
It is important to have a guarantee of at least 5 years because there are LED tubes of poor
quality on the market.
ECO tubes
The conventional T8 tubes used today, can be exchanged for the equivalent ECO/ES tubes that
use 10 % less energy. These tubes are called ECO by Philips and ES by Osram and can be applied
in existing fixtures (also other manufactures have the same type of fluorescent tubes).
ECO/ES tubes provide basically the same light output and last as long as current fluorescent
tubes. The investment cost is an additional cost compared with the conventional T8 tubes and
amounts to approximately € 3 each.
Because the payback time is shorter than the expected technical lifetime of the conventional
T8 tubes, and the LCC calculation gives a positive result, the measure is profitable.
23
Ventilation
Ventilation is using approximately 59 600 kWh
el
/year. Most of the buildings are not ventilated
and the majority of the energy consumption is used by the filter for sand blasting and polishing
(see measure below).
There is also a ventilation unit for building 7a with heat recovery that runs 1-shift.
Sand blasting
Our logging of the electricity use for sand blasting filter (ventilation fan, 18 kW) show that this
fan is in operation between 06.00 and 21.30 weekdays, with a 30 minute break in the morning
(09.30 – 10.00) when the fan is switched off. The base level for the fan is at 14,5 kW and when
actual operations are done the power demand increases to 17,6 kW. It seems that the main
part of the electric energy use here is for keeping the fan running, not necessarily transporting
anything out from sand blasting or/and polishing to the filter.
Measure, fan with variable frequency drive
We propose that the fan motor be equipped
with a variable frequency drive, VFD; that
can reduce the fan speed (motor frequency)
to 20 Hz when there are no operations going
on. In addition to this there should be
automatic dampers installed for every work
station/exhaust point so that there is no
suction when no work is being done (except
a small flow in order to keep the motor
running at 20 Hz). As one or more dampers
open there will be a change in duct pressure
and the fan can increase its speed via the VFD.
Calculating annual electric energy use for this fan gives us a number of 50,000 kWh/year. The
proposed modification/investment can easily reduce the annual electric energy use by 50 %,
or 25,000 kWh of electric energy per year, worth 2,200 Euros per year.
The investment cost is estimated to be approximately 5,000 Euros, giving a pay-off time of 2.3
years.
Saving
Electricity:
25 000
kWh/year
Cost reduction
2 200 €/year
Costs
Investment cost:
€ 5 000
Financial calculations
Payback:
2,3 years
LCC (cost saving 10 years):
€ 9 760
24
Compressed air
The compressed air system is using 134 000 kWh/year and is served by three compressors,
model Kaeser ASD 37 with rated power of 22 kW, Kaeser Airtower19 with rated power of 11
kW and Speiarke Lialter with rated power of 5,5 kW. Speiarke Lialter is only used if pressure is
too low in building 2a.
The average power use during one day of production is 20,5 kW. The air pressure in the system
is around 7.5 bar.
Because some divisions are working 2 and 3 shifts there is a need for compressed air from
Monday morning to Friday afternoon.
Measure, compressor with variable frequency drive
Invest and install a compressor with variable
speed and use this as the main compressor.
Keep Kaeser ASD 37 T as a reserve
compressor only used during stop for main
compressor.
The need for compressed air varies widely
during a production day. According to
measurements made by Kaeser, spring
2016, the airflow during peaks around 7 am
and 1 pm is above 5 m
3
/min. During the
third shift the airflow is only 0.6 m
3
/min.
The power consumption for compressors does not vary as much. The average power for
compressors during first shift (with peak loads) is 20,5 kW and during third shift 15,6 kW.
A compressor with variable frequency drive would much better adapt the production to the
need for compressed air and reduce the power consumption when the need is low.
Measure, Kaeser ASD 37 T, air transportation and heat recovery
Saving
Electricity:
60 000
kWh/year
Cost reduction
5 300 €/year
Costs
Investment cost:
€ 8 900
Financial calculations
Payback:
1,7 years
LCC (cost saving 10 years):
€ 26 660
Saving
Electricity:
1 500 kWh/year
Natural gas:
70 000
kWh/year
Cost reduction
2 700 €/year
Costs
Investment cost:
€ 3 000
Financial calculations
Payback:
1,1 years
LCC (cost saving 10 years):
€ 15 120
25
The air compressor located in the compressor room between buildings 2 and 3 at XXXX XXXX
site has a non-functioning heat recovery/cooling system that can be fixed so that two main
significant goals can be achieved:
The system, with a ventilation duct leading from outside into the compressor room, does not
have sufficient cooling capacity. Therefore, a split cooling unit, with 800 W electricity use and
2.2 kW cooling capacity is placed in the compressor room to help during warm days.
The system does not have appropriate exhaust capacity either. A hood on top of the
compressor is located too close to the top of the compressor and the exhaust air duct is
broken/separated up at ceiling level before the duct leaves the room and continues to the
environment (outdoors) or into the marble
grinding/polishing room. See photos:
This system must be re-constructed so that cooling air can be drawn from outside during the
summer and from the marble department (or from the cleaner part of Kominki, building 3) in
the winter and so that the exhaust can be evacuated to the outside during the summer and
back to where the air was taken from, during the winter. By fixing this the compressor can get
sufficient supply of fresh air and the warm air that is exhausted from the compressor can be
used to replace the use of natural gas for heating during the cold season. Parts of the existing
air distribution system can be used also in the future:
26
By fixing the system it is calculated that the extra
cooling unit does not have to be used anymore,
saving 1,500 kWh of electricity during the summer.
The energy recovered from the compressor during
the heating season can be used instead of natural
gas, saving a total of 60,000 kWh of natural gas
every winter, net savings. With an expected annual
efficiency of the gas boilers at 85 % the gross
natural gas savings amount to over 70,000 kWh per
year. Total savings, 1,500 kWh of electricity and
70,000 kWh of natural gas, are worth 2,700 Euros per year.
The investment cost is estimated to be around 3,000 Euros, making the pay-back time as short
as 1.1 years.
Measure, Kaeser Airtower 19, heat recovery and filter change
Saving
Natural gas:
14 000
kWh/year
Cost reduction
550 €/year
Costs
Investment cost:
€ 2 000
Financial calculations
Payback:
3,6 years
LCC (cost saving 10 years):
€ 1 690
27
This compressor is located in a small building located close to warehouse 11 and not far from
building no. 12. Measured data for this compressor shows that it annually uses approximately
22,500 kWh, every week approximately 430 kWh of electricity.
When visiting the compressor room, we noticed that the compressor’s air filters were very
dirty, see photo. This makes the compressor run very inefficiently since it cannot easily get the
air that it needs to generate the compressed air. It is like breathing through a straw, like having
asthma.
Our recommendation is that the air intake filters should be
replaced more regularly, maybe as often as once every month
if needed. This will increase the compressor efficiency
significantly although it is not easy to calculate the savings.
Also the heat that this compressor generates could be used to
heat buildings instead of only using natural gas for heating.
Since the compressor house is closest to warehouse 11 it
should be most natural to utilise the recovered compressor
heat in this warehouse. However, the warehouse already
utilises recovered heat from the sand blasting filter, located
outside building 10, why we recommend installation of a fan,
a manual damper to choose summer or winter operation and
an insulated duct leading the recovered heat into building 12
which is also close by the compressor house for compressor ASD 19.
The energy recovered from the compressor during the heating season can be used instead of
natural gas, saving a gross total of over 14,000 kWh of natural gas every winter, worth 550
Euros per year.
The investment cost is estimated to be around 2,000 Euros, making the pay-back time become
3.6 years.
28
Space heating and domestic hot water
Natural gas is used for space heating and domestic hot water. The heat is distributed through
a hydronic heating system with radiators and aerotempers. Smaller local systems also exist, for
example building 6 has its own gas burner. The amount of natural gas used for space heating
was 1 250 000 kWh and for domestic hot water 50 000 kWh during the twelve month period
from 2015-08-01 to 2016-07-31.
The KPI value for space heating amounts to 113 kWh/m
2
and year (based on the same twelve
months’ period) which doesn´t seems to be particularly high. However, if one takes into
account that most buildings are not ventilated and therefore do not have any ventilation losses
this KPI-value is higher than for a normal building with similar production.
The high KPI-value is explained by deficiencies in the building envelopes. Measures that
decrease the need for space heating are given in chapter 0, 0, 0 and 0.
The electricity for space heating and domestic hot water shown in Chart 3 is the energy used
by the main circulation pumps which annually amounts to 9 000 kWh
el
respective 2 000 kWh
el
.
29
Production
The processes in the production annually use 140 000 kWh
el
and 655 000kWh
n.ags
. Separate
measurement has been done for the water cutting machine. Other processes have been
estimated by measuring electricity centrals for different buildings. These measurements can
be found in appendices.
There is small idle power consumption during weekends and this is not derived from
production according to measurements. The idle power is as low as 10 kW and is believed to
be from circulation pumps for heating system and from outside lighting.
Furnaces, building 12
In building 12 there are some gas-fired furnaces that are used to cure some of the finished
products. The process is now in operation during night time and the temperature in the
furnaces vary between 80 and 120
o
C. According to the personnel it is not easy to maintain the
correct temperature (or even to know which is the correct temperature) in the furnaces
because it varies so much depending on how close to the openings the products are.
Before the furnaces were installed the products cured in room temperature but it took longer
time and of course this also requires larger space for storage of products while curing.
There also used to be a heat recovery system, using excess heat from the furnaces to heat
some of the premises (a warehouse) but that system is no longer in use due to problems with
CO
2
in the air (rest product from combustion of natural gas). When heat could be used also for
heating during the heating season, then at least the usage of natural gas had a doubled value.
Now it is questioned whether to continue to use gas-fired furnaces, to switch to electric
furnaces or to go back to getting the products cured in room temperature.
After evaluating the power situation, costs of various energy sources etc. we strongly
recommend that there should not be a change to electric furnaces; costs will be too high for
the electricity and there will also be some implications on the rate structure and the potential
power interruptions that follow with exceeding a demand of 300 kW.
From an energy efficiency point of view it is best to not use any furnaces at all but we realise
that productivity goals may call for some increased curing time. In case furnaces must be used
we recommend gas-fired furnaces but that some investments are made to recover heat from
the furnaces through a heat exchanger, without transferring CO
2
to premises where people
work.
30
Appendices
Overview of site
Figure 4: Overview of site XXXX with building numbers.
31
Lighting survey
32
Premises
Type
Installed power
[kW]
Run time
[h/year]
Energy use
[kWh/year]
Building 2 - Marble
T8 58W
5,4
2 160
11 800
Building 2a - Wood
department
T8 58W
3,3
2 160
7 100
Building 2 -
Compressor room
T8 36W
0,1
2 160
200
Building 2 - Electricity
central
T8 36W
0,1
2 160
200
Building 3 -
Fireplaces
T8 58W
22,2
2 880
63 800
Building 3 -
Fireplaces
warehouse
T8 58W, Metal halide
120W
6,8
2 880
19 500
Building 3a - World
warehouse
T8 58W
4,5
2 160
9 700
Object 4a - Tent
warehouse
T8 36W
0,5
2 880
1 500
Building 5 - Wood
T8 36W, High
pressure sodium
150W
1,1
2 160
2 400
Building 6
T8 58W
1,2
2 160
2 600
Tent warehouse "C"
T8 58W
1,5
2 160
3 200
Building 7
T8 58W, T8 36W
10,1
2 160
21 800
Building 7a - Foundry
T8 36W
2,1
2 160
4 600
Building 8 - Welding
T8 58W
2
2 160
4 400
Crusher
T8 58W
1
2 160
2 100
Office
T8 36W, T8 18W
2
2 400
4 900
Building 10 - Slate 1
T8 58W
4,4
2 400
10 400
Building 10 - Slate 2
T8 58W
3,1
2 400
7 500
Building 11 - Canteen
T8 58W
1,4
2 160
2 900
Building 11 - Dressing
room
T8 58W
2,9
2 160
6 200
Building 11 -
Corridors, Staircase
T5 28W
0,1
2 160
300
Building 11 -
Warehouse SL. TH
T8 58W, LED 102W
3,1
2 400
7 300
33
Building 12 -
Thermotte
T8 58W
12,2
5 760
70 500
Building 13 -
Laboratory
T8 58W, T8 18W
1,7
2 160
3 600
Outside
Metal halide 120W,
High pressure
sodium 150W, Hg
125W
4
4 000
16 100
Total
96,7
284 600
Table 4: Performed lighting survey. An overview of buildings and premises are shown in
appendices in Figure 4.
34
Calculations
Building
Seal the industrial door in Building 2 and 7.
Transmission losses have been estimated by standard value to 60 kWh / year and cm
2
. The
area of the field is measured to 700 cm
2
.
The investment cost used in the calculation is € 500.
The parameters for the LCC calculation is, calculation period 10 years, discount rate 10 % and
annual energy price increase 2 %.
Apply an extra insulated glass unit on the windows in Building 6.
U-value for the current window is estimated to 6 W/m²K. It is considered possible to reduce to
1,3 W/m²K with an extra insulated glass unit. The window area amounts to 36 m² and the
indoor temperature to 18°C.
The investment cost used in the calculation is € 4 000.
The parameters for the LCC calculation is, calculation period 15 years, discount rate 10 % and
annual energy price increase 2 %.
Construct a well-insulated wall that replaces the windows in Building 7.
U-value for the current window is estimated to 5 W/m
2
K. It is considered possible to reduce to
0,3 W/m
2
K. The window area amounts to 65 m
2
and the indoor temperature to 18°C.
35
The investment cost used in the calculation is € 7 200.
The parameters for the LCC calculation is, calculation period 20 years, discount rate 10 % and
annual energy price increase 2 %.
Repair broken window in Building 7.
U-value for the current window is estimated to 35 W/m²K. It is considered possible to reduce
to 1,3W/m²K. The window area amounts to 1,2 m² and the indoor temperature to 18°C.
The investment cost used in the calculation is € 260.
The parameters for the LCC calculation is, calculation period 20 years, discount rate 10 % and
annual energy price increase 2 %.
36
Lighting
Change of lighting to T5
The new lighting is calculated to provide an estimated key value. The change applies to the
room(s) Building 12 Thermotte, Building 3 Fireplaces.
The investment cost used in the calculation is € 14410.
The parameters for the LCC calculation is, calculation period 10 years, discount rate 10 % and
annual energy price increase 2 %.
Change of lighting to ECO/ES tubes
The following savings have been calculated for the measure: Electricity 42 200 kWh/year. The
reduced energy costs have been estimated at 4 250 €/year.
The investment cost used in the calculation is € 15 560.
The parameters for the LCC calculation is, calculation period 10 years, discount rate 10 % and
annual energy price increase 2 %.
Ventilation
Sand blasting, fan with variable frequency drive
The following savings have been calculated for the measure: Electricity 50 000 kWh/year. The
reduced energy costs have been estimated at 2 200 €/year.
The investment cost used in the calculation is € 5 000.
37
The parameters for the LCC calculation is, calculation period 10 years, discount rate 10 % and
annual energy price increase 2 %.
Compressed air
Compressor with variable frequency drive
The following savings have been calculated for the measure: Electricity 60 000 kWh/year. The
reduced energy costs have been estimated at 5 300 €/year.
The investment cost used in the calculation is € 8 900.
The parameters for the LCC calculation is, calculation period 10 years, discount rate 10 % and
annual energy price increase 2 %.
Kaeser ASD 37 T, air transportation and heat recovery
The following savings have been calculated for the measure: Electricity 1 500 kWh/year,
Natural gas 70 000 kWh/year. The reduced energy costs have been estimated at 2 700 €/year.
The investment cost used in the calculation is € 3 000.
The parameters for the LCC calculation is, calculation period 10 years, discount rate 10 % and
annual energy price increase 2 %.
Kaeser Airtower 19, heat recovery and filter change
The following savings have been calculated for the measure: Natural gas 14 000 kWh/year. The
reduced energy costs have been estimated at 550 €/year.
The investment cost used in the calculation is € 2 000.
The parameters for the LCC calculation is, calculation period 10 years, discount rate 10 % and
annual energy price increase 2 %.
38
39
Measurements
Measurement 1: Production, Water cutting.
Unit
Name
Ave
Min
Max
Energy
(kWh)
[kW]
Power
1,22
0,00
58,94
226
40
Measurement 2: Electricity central, Building 7.
Unit
Name
Ave
Min
Max
Energy
(kWh)
[kW]
Power
8,68
0,72
54,25
1 619
41
Measurement 3: Electricity central, Building 3.
Unit
Name
Ave
Min
Max
Energy
(kWh)
[kW]
Power
18,20
6,60
52,05
3 396
Measurement 4: Electricity central, Office.
Unit
Name
Ave
Min
Max
Energy
(kWh)
[kW]
Power
1,34
0,31
10,56
250
42
Measurement 5: Electricity central, Building 11, 3a, 12.
Unit
Name
Ave
Min
Max
Energy
(kWh)
[kW]
Power
31,28
1,44
89,84
5 835
43
Measurement 6: Electricity central, Building 6.
Unit
Name
Ave
Min
Max
Energy
(kWh)
[kW]
Power
2,78
0,00
54,63
519
44
Measurement 7: Electricity central, Building 2 (R5).
Unit
Name
Ave
Min
Max
Energy
(kWh)
[kW]
Power
0,20
0,00
2,87
4
45
Measurement 8: Electricity central, Building 2 R1 R2 (1).
Unit
Name
Ave
Min
Max
Energy
(kWh)
[kW]
Power
1,20
0,00
8,62
25
46
Measurement 9: Electricity central, Building 2 Polerka.
Unit
Name
Ave
Min
Max
Energy
(kWh)
[kW]
Power
0,00
0,00
0,00
0
47
Measurement 10: Electricity central, Building 2 R3.
Unit
Name
Ave
Min
Max
Energy
(kWh)
[kW]
Power
2,54
0,00
19,26
54
48
Measurement 11: Compressed air, Kaeser ASD37T.
Unit
Name
Ave
Min
Max
Energy
(kWh)
[kW]
Power
13,14
0,00
24,90
2 448
49
Measurement 12: Compressed air, Kaeser Airtower 19.
Unit
Name
Ave
Min
Max
Energy
(kWh)
[kW]
Power
2,72
0,00
13,80
506
50
Measurement 13: Electricity central, Building 2 R1 R2 (2).
Unit
Name
Ave
Min
Max
Energy
(kWh)
[kW]
Power
3,50
0,00
22,74
73
51
Measurement 14: Ventilation, Building 7a.
Unit
Name
Ave
Min
Max
Energy
(kWh)
[kW]
Power
1,22
0,00
6,36
25
52
Measurement 15: Ventilation, Sand filter.
Unit
Name
Ave
Min
Max
Energy
(kWh)
[kW]
Power
8,23
0,00
17,68
170
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53
