Energy Audit of Vitez Municipal Administration Building

Energy audit ofVitez municipal administration building

ENER-SUPPLY
ENergy Efficiency and Renewables–SUPporting Policies in Local level for EnergY

Energy audit of Vitez municipal administration building

Partner: REIC, Bosnia and Herzegovina

1. Introduction

Energy audit for the building of Vitez municipality was conducted within the scope of the project ENER-SUPPLY- ENergy Efficiency and Renewables - SUPporting Policies in Local level for EnergY.The Project is implemented in the countries of Adriatic-Ionic region within the development programme for South-Eastern Europe. The project is implemented by the consortium consisting of 14 regional companies. The leader of the consortium is the Potenzamunicipality, Italy, and Regional Education and Information Centre for South-Eastern Europe (REIC) participates in the Project on behalf of Bosnia and Herzegovina (BiH). REIC has identified the Central Bosnia Canton as the territory in BiH where the project should be implemented. The implementation period is from November 2009toNovember 2012.

The main objective of the project is to provide assistance to local authorities in the area of using potentials of renewables and improvement of energy efficiency when it comes to energy utilisation for the purpose of sustainable development of the Canton. The Project is especially focused on removing barriers against using renewables and improvement of energy efficiency at local level.

In January and February 2011, a five-day training course was conducted for the employees of municipalities and government authorities of the Central Bosnia Canton concerning energy management. The training covered the following topics:

- analysis of energy supply (6 hours),

- development of energy balance (16 hours) and

- conducting of energy audit (16 hours).

There were on average 19 trainees for each of the topics. REIC provided local and international trainers and training material. All trainees received training certificates. The training was aimed at increasing energy efficiency of the municipalities and Canton. In that context, trainees were trained on methodology of conducting energy audit for the purpose of identifying measures for increasing energy efficiency. In the practical part of the training, the trainees participated in the conducting of energy audit for the building of Vitez municipality. The audit for the building was conducted following the proposal of the representatives of the Municipality involved in the ENER SUPPLY Project.

In addition to energy management course within the scope of ENER SUPPLY, in the period fromSeptember – October2010,a 40-hour training course was conducted concerning renewables. The focus of the course was the utilisation of biomass, construction of small hydro power plants and wind plants, utilisation of geothermal energy and financial evaluation of projects based on utilisation of renewables. Potentials of surveyed renewable energy sources in BiH and Central Bosnia and Canton were presented, as well as barriers against utilization of the potentials.

1. Methodology of conducting energy audit

There are two major types of energy audit (energy survey):

- preliminary walk-through audit

- detailed audit.

Phases of the walk-through audit are the following:

• preparatory phase – collection of data concerning properties of the facility, major energy systems and energy costs,
• interviewing the responsible person in the facility,
• site visit – visual examination of the energy status of the building envelopeand all technical systems, identifying basic characteristics of energy consumption and places of major energy losses,
• analysis of data collected and final report – survey of major problems in energy consumption with recommendations to improve energy efficiency and identify need to implement the detailed energy audit.

A walk-through energy audit does not include calculations, measuring or modelling of energy consumption. A main purpose of the walk-through audit is to identify the potential for energy consumption and make decision concerning conducting of a detailed energy audit.

The detailed energy audit includes a detailed energy analysis of al construction and technical systems within the facility. For the existing facilities, depending on their purpose, energy costs are analyzed during 36 months on average for the purpose of modeling of energy consumption and assessing energy needs within the facility. If needed, the analysis is complemented with the measuring of consumption of electricity consumption, heating losses, and ventilation losses in the facility, etc. which is important for the establishment of energy losses in certain systems.Collected data are processed and energy properties of the analyzed facility are calculated.

Phases of the detailed energy audit are the following:

• meeting and interviewing key personnel in the facility – manager and users/owners,
• examination of the existing design documentation,
• examination and analysis of bills concerning heating and electrical energy consumption, as well as water for optimum 36 months (compulsory only for public facilities),
• visiting and scrutinizing the facility and undertaking consumption measuring, following the identifying of key gaps,
• interviewing key personnel in the facility again,
• analyzing and processing of collected data,
• identifying measures for improvement of energy properties of the facility and improvement of energy efficiency,
• energy related, economic and environmental evaluation of the recommended measures and
• preparation of the report with conclusions and recommendations and presenting them to key people.

Within the energy audit of the building of the Vitez municipality, two energy systems within the building were analyzed (i) space heating system i (ii) system using electricity. Energy audit was conducted using the following methodology:

-users of the building fill in the questionnaire

REIC received the questionnaire from the ENER SUPPLY project partner responsible for the energy management project package and it is the Greek public institute for energy efficiency and renewables (CRES). REIC provided translation of the questionnaire into local language and delivered it to the Municipality.

-Visiting the building in order to collect inputs

This phase includes the measuring of the level of heating losses by means of the infrared camera and the measuring of the composition of flue gases from the boiler in order to determine the level of efficiency of the boiler and meeting the requirements of limit values of emission. All measuring devices used in this phase is regularly calibrated.

-Analysis of data collected

Based on the analysis, measures for improvement of energy efficiency and decrease of energy consumption costs are recommended in this phase. Preliminary analysis results were presented at energy management workshop (practical part of energy management training course) in the Municipality on 10 February 2011.

Although the energy audit of the building of the Vitez municipality included certain measuring, the conducted audit was still a walk-through audit.

1. Description of the present use of energy in the building of Vitez Municipality

The building of VitezMunicipality was built in 1960. The total area of the building is 1,023 m2. The building consists of the ground floor and other two floors. The total area of the main premises (office premises) is 730 m2, and the remaining area is about 293 m2which consists of corridors and toilets.

The facade of the building lacks heating insulation.The roof also lacks insulation.In the beginning of 2010, new windows and entrance door were installed. These are PVC products.

The building is used 8 hours a day every working day. There are 70 staff members (users of the building) and about 400 visitors per day.

3.1.Description of the existing heating system of the building of Vitez municipality

The heating in the building of Vitez municipality is provided by the boiler fuelled on heating oil, power 300 kW, by hot water through the radiators installed in the rooms. The same boiler is used for heating the next-door police building. The boiler is about five years old and is in quite good condition. There is a regular maintenance provided. The measuring of composition of flue gases and loss of energy in flue gases has been conducted. The police building, the heating of which is provided through this boiler, is of total area of 781 m2. Therefore, the total area the heating of which is provided through the boiler of power of 300 kW is1,804 m2, which means that the installed power is about 165 W/m2. This is much more than it is now usually installed (80 – 100 W/m2). The consequence of this is that the boiler during most of the season works at very low load (below 50%), which causes lower efficiency than envisaged.

The heating systemis designed for inlet water temperature of 90°C and outlet of 70°C. The radiators have simple regulation valves (without thermostatic heads).Average working time of the heating system during the season is 10 hours a day.

There is no system of separate measuring of energy consumption for the Municipality and police building. Total annual consumption of heating oilfor heating of both buildings is about 21 tons.

According to users of the building, the above described heating system does not provide comfotable temperature, therefore the space is additionally heated with electrical heaters.

3.2.Utilisation of electrical energy in the building of Vitez municipality

Electrical energy is used for:

-lighting,

-office equipment,

-heating of sanitary water, and

-additional heating of space by means of electrical heaters.

Taking into account that the time of using of the building is 8 hours a day every working day, and estimated using of lighting 4 hours a day, electricity used for lighting is low. The total installed capacity of lighting is 9,68 kW. Of that 2,34 kW is for bulbs with hot wire and 7,34 kW neon bulbs. Neon bulbsare used in offices and bulbs withhot wire in corridors and toilets.

Electrical boilers of total power of 5 kW are used for heating of sanitary water. Estimated time of operation of the electrical boilers is 4 hours a day every working day.

Electrical heaters are used to additionally heat the space cince, according to users of the building, radiators do not heat the space sufficiently. There is no date on total power of electrical heaters. Using electricity for heating significantly increases costs for energy in two aspects (i) increased consumption of active energy and (ii) increased costs of calculated peak power.

1. Measuring of composition of flue gases, losses of energy in flue gases of boiler and thermographic screeningof facade of the building of Vitez municipality

Measuring of concentration of polluting substances in flue gases has been conducted by means of a device MRU VARIO PLUS INDUSTRIAL (Figure 1).The measuring was conducted on 10 February 2011.

Figure 1 Device MRU VARIO PLUS INDUSTRIAL

Measuring characteristics of the measuring device are provided in Table 1.

Table 1. Measuring characteristics of the g device MRU VARIO PLUS INDUSTRIAL

O2 / 0 – 21 %.
CO (H2) / 0 – 10,000 ppm
COlow (H2) / 0 – 500 ppm
NO / 0 –5,000 ppm (0.1 ppm resolution)
NO2 / 0 – 1,000 ppm (0.1 ppm resolution)
SO2 / 0 – 5,000 ppm
CO2 / (NDIR) 0 – 30 Vol. %

Measuring of composition of flue gases was conducted in the pipe which connects the boiler and chimney. The measuring took about 15 minutes. The measuring of the concentration of the following substances was conducted on four occasions:

- nitrate oxides presented as NO2

- sulphur dioxide SO2

- carbon oxide CO

- carbon dioxide CO2

- oxygen O2.

In addition to measuring of these parameters, measuring was conducted of temperature of flue gases based on which the device calculated boiler losses in flue gases. On the basis of the losses, the estimate of the level of efficiency of the boiler was provided.

The Table 2provides the results of the measuring of composition of flue gases from the boiler used for heating of the building of the municipality assemby.

Table 2 Results of the measuring of composition of flue gases (calculated for referentoxygen concentration of3%and dry flue gases)

Parameter / Unit / Value
CO / mg/m3 / 31.00
SO2 / mg/m3 / 164.25
NOx / mg/m3 / 67.25
O2 / % / 9.38
CO2 / % / 8.33
Losses of energy in flue gases / % / 5.45

The concentration of polluting substances in flue gases of the examined boiler is below limit value of emissions in FBiH. The surplus of air is slightly higher than usual value, and the temperature of flue gases is quite low. Both phenomena are likely to be the consequence of the low level of the boiler loadduring the time of measuring. Losses in flue gases are relatively small (consequence of low temperature of flue gases). In addition to losses in flue gases, there are losses caused by emission of heat and incomplete combustion (CO in flue gases). Taking into account usual correlations between all losses of energy in the boiler, the boiler level of efficiency has been estimated to be 88%.

On 28 January 2011, thermal imaging of the facade of the building of the municipal administration was conducted in order to identify spots where significant losses of the heating energy occur.External temperature during thermal imaging was -5°C. Specific images are provided in Figures 2, 3, 4, 5 and 6.

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Image2Thermal image of windows on the building of the Vitez municipal administration (South)

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Figure3Thermal image of windows on the building of the Vitez municipal administration (South)

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Figure4Thermal image of windows on the building of the Vitez municipal administration (North)

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Figure 5 Thermal image of facade on the building of the Vitez municipal administration (North)

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Figure 6 Thermal image of roof on the building of the Vitez municipal administration (North)

There are the following conclusions based on thermal images:

-Windows on the Vitez municipal administration building have a relatively low coefficient of heat transfer,however their ventilation losses are slightly increased, leading to a conclusion that windows were not properly installed.

-The facade is partly damaged and wet, which causes heat losses (Figure 5),

-The roof of the building lacks insulation, therefore heat losses through the roof are enormous,

-Radiators are not visible on the thermal image (rather because of low temperature of water in radiators than because of good facade).

Given the fact that the next-door police building uses the same heat source, thermal imaging of that building was also conducted. This building is in worse condition concerning the heat insulation mainly because the quality of windows is bad. The imaging helped to determine the exact consumption of energy of the municipal building and police building respectfully.

If there is no boiler regulation, the problem of heating of buildings of significantly different energy characteristics like municipal assembly and police building, is that one keeps trying to heat the building with weaker heat insulation. At the same time, the building with better insulation is usually overheated and the users usually open the windows in order to cool space. In this specific case, such thing does not happen since the heat insulation of both buildings (especially the police building) is too bad and the existing boiler cannot adequately heat the municipal assembly building alone.

1. Proposal for reducing of heating costs for Vitez municipal assembly building
2. Replacement of the boiler fuelled by heating fuel by boiler fuelled by pellet

As described in section 3.1., the building of the municipal assembly is heated by the boiler fuelled by heating oil. Table 3provides comparison of prices of energy from various energy sources with the prices at the beginning of 2011 in BiH.

Table 3Prices of energy from various energy sources (prices at the beginning of 2011 inBosnia and Herzegovina)

Note: Consumption of peak load in electricity consumption was not taken into account

Table3shows that heating oil energy is the most expensive. Taking into account that the total cost of consumption of an energy source includes the cost of labour force (and some other costs), it makes sense to compare different prices of energy of the system with automatic feeding. In other words, it is not possible to compare prices of energy sources for the systems with manual and automatic feedingand make conclusions on the basis of that. Taking this into account, it makes sense to compare the price of energy from heating oil with prices of energy from natural gas, wood chips, pellet and electricity. The price of energy from fuel is about twice as expensive as that from natural gas and about three times as expensive as that from pellet. If electricity peak load costs are somehow taken into account, the price would exceed heating oil energy price. The price of energy from wood chips is about five times cheaper than the price of energy from fuel. However, the market of wood chips in BiH has not been much developed; therefore, the possibility of using wood chips instead of heating fuel has not been considered.

In order to assess the cost-effectiveness of using pellet instead of fuel, the following was taken into account:

-investment in two boilers powered by pellet each of 200 kW,

-prices of fuel and pellet at the beginning of 2011,

-level of efficiency of boilers powered by pellet 92%[1],

-two boilers powered by pellet of total power 400 kW would be sufficient for adequate heating of both buildings, therefore electrical heaters would not be necessary. Thus, electricity costs would be reduced.

-twice higher costs of maintenance of boilers powered by pellet than of the existing boiler powered by heating oil and