Energy audits (Part II). Phase and development analysis.
Determining the concept or what is an energy audit it involves encompassing a series of specific circumstances within the building. The Energy audits It can be defined as a comprehensive investigation of each and every one of the aspects, both technical and economic, that directly or indirectly affect the consumption of the different energies in a Building, whoseobjective is to establish a rational set of reforms or improvements aimed at a rational use of the Energy.
Said improvements must not imply a reduction in the quality of the services provided, in the productivity or in the habitability of the Building, and may even entail auxiliary improvements in these aspects.
As a continuation of the previous post, we are going to complement the information provided, explaining the standard procedure working on the development of a example energy audit by stages and some practical example. Normally the audit contemplates a study by phases or stages of the object building, its facilities and its equipment, which are the ones detailed below, so we are going to try to unravel how to do energy audits:
1.- Data collection and audit planning:
In this phase, a compilation of as much information as possible in relation to the building will be carried out, both in relation to its constructive characteristics and energy systems, although examples of audits There are many, we are going to explain the procedure step by step, which can be divided into several sub-phases:
Phases and stages of an energy audit in buildings
We attach this diagram to have a global perception of the different points of inspection before the building and documentation necessary.
How to do an energy audit
1.1.- Interview with those responsible for the building and collection of information about it as well as its occupants, especially on the building systems of the envelope, billing for each of the energy consumption, technical characteristics of its facilities, use and occupation regime, environmental conditions and characteristics of the work carried out, real weather data of the area where the building is located, etc.
1.2.-Planning the audit.
1.3.- On-site visit and visual inspection to check the current status of the same and to be able to identify possible problems or deficiencies, being recommended on the one hand to carry some type of file or checklist where to reflect the current status and contrast it with the information collected, as well as to be accompanied by a maintenance manager and another person who knows the condition of the building.
For the compilation of the information in a coherent way three articles of interest with abundant technical documentation:
- Material properties (So we can see their technical characteristics)
- Guide to glazing in enclosures (With all types of carpentry and details)
- Construction techniques and types
1.4.- Carrying out a questionnaire to the users of the property In it you can collect information about the state of the building, its thermal comfort, as well as the habits and behaviors of its occupants that may lead to improper use or management of its facilities and equipment.
1.5.- Simulation to estimate the thermal loads and demands of the building. In this phase, a simulation of the building's energy behavior will be carried out, through some of the currently existing programs for this purpose, in which a theoretical estimate of the building's loads and demands will be made.
1.6.- Preliminary report. At this point the auditor technician must carry out an evaluation and analysis of all the data collected, studying them in depth, as well as establishing a diagnosis of the state of the building and its facilities.
2.- Measurements and recording of factors related to the energy balance:
2.1.- Planning of the measurement process. The measurement phases as well as the necessary equipment or instruments must be planned. In addition, the areas where such measurements are to be made must be identified.
2.2.- Measurement equipment and records. The most frequent parameters to be measured in the study building, as well as the equipment used are the following:
Taking of records of the Building and its envelope:
|
Evaluated parameter |
Measure instrument |
Location, measurement area |
|
Indoor conditions: Wet and dry temperature from air |
Thermometer |
Rooms and work areas Habitable housing areas. |
|
Indoor conditions: Relative air humidity |
Hygrometer |
|
|
Thermal transmittance: Heat flow through a constructive element. |
Thermoflowmeters |
Facades or other enclosures of the thermal envelope. Partitions with non-habitable spaces, etc. |
|
Air leaks |
Infiltration meter |
Door and window seals. |
|
Thermal bridges or zones with heat losses. Areas with deteriorated or uninsulated thermal insulation. |
Thermographic Cameras |
Encounters of facades with slabs, façade with pillars, window perimeters (gutters, jambs, lintels), meeting slab with roof or slabs. |
Taking records of the facilities:
For the collection of information in the facilities, the equipment commonly used is the following:
Electrical network analyzer:
A network analyzer allows you to measure or calculate the parameters of an electrical network such as voltage, intensity, power, active and reactive energy, power factors, etc. It also allows you to memorize and record this information so that you can work on it later.
Flue gas analyzer:
It is a piece of equipment that allows the analysis of combustion gases capable of measuring or calculating the parameters that determine the characteristics of the combustion process in a certain equipment that consumes fuel, be it a heater, a boiler, an engine, etc. The parameters it can measure are oxygen concentration, carbon monoxide, nitrogen oxides, sulfur oxides, draft, ambient air and gas temperature, combustion rate, etc.
Luxmeters:
They are used to measure the level of illumination or illuminance (in lux), in a certain area, being generally light and simple that has a photosensitive probe and an analyzer.
Other equipment used:
In addition to the above, other frequently used measuring devices are the ammeters, to measure electrical intensity, pressure gauges to measure the pressure of a fluid, flowmeters to measure the flow of a fluid through a pipe, etc.
This video explains the operation of some of these measurement equipment for energy audits:
3.- Study of the energy balance:
In this phase, all the information collected in the two previous phases is processed and analyzed, both the one referring to the state of the building and energy facilities, as well as that obtained in the energy simulation and in the records in order to obtain conclusions in relation to:
- How electricity consumption is distributed according to the tariff periods, determining what is said real consumption in the valley, flat and peak periods. Likewise, it must be obtained which is the distribution of said consumption according to area or zone.
- Graphic representation and analysis of the parameters of electricity consumption and of the rest of energies or fuels to be able to detect the evolution of annual, daily and hourly consumption, detect the operation of equipment outside working hours, analyze the behavior of the power factor, etc …
- Carry out a study of the building's energy billing From the data previously obtained, to be able to determine if the contracting conditions are the most appropriate or there is another rate that better adapts to the conditions or way of consuming energy in our building, so it is also necessary to know the structure rate for each energy service.
- Comparison between the theoretical energy consumption results of the simulation with the real ones obtained from the billing, assessing what factors can influence the loss of energy in each installation and generate excessive consumption, in order to identify which parts of the installation may be wasting energy or which area of the thermal envelope has inadequate thermal behavior.
4.- Analysis to improve the building's energy performance:
4.1.- IDENTIFICATION OF IMPROVEMENT PROPOSALS.
The improvements that must be introduced in the building will be proposed to improve the energy performance of its envelope and its facilities, these improvements can be grouped into several blocks corresponding to the construction elements, air conditioning and air conditioning systems, as well as regulation and control equipment, energy recovery and introduction of renewables.
4.2.- ANALYSIS OF ECONOMIC VIABILITY.
All the proposed measures must be studied to analyze the cost necessary for their implementation, the energy savings achieved, the payback or amortization period, as well as what the problems or inconveniences that may be associated with their implementation may be.
5.- Final results and issuance of the Report:
In this last phase, a report will be made that reflects the objectives of the audit, the description of the building and its facilities, the measures taken on site, as well as a summary of the results and recommendations together with the preventive and corrective measures for to be able to eliminate the problems detected, being able also to include an informative campaign to improve the behavior of the users of the building.
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Let's remember the access to the article … »Energy audits (Part I). Definition, scope of action and regulations«. It is also worth highlighting the compilation of guides and manuals where we will find more informationHERE.
Added February - 2016: It was published in Spain onRoyal Decree 56/2016 referent on energy audits in Spain by which the European Directive on energy efficiency 2012/27 / EU is partially transposed.
Practical examples of audits:
- Practical example… HERE. The work has referred to the Mediterranean Center for Marine and Environmental Research (CMIMA) of the CSIC as the basis for the development of the project.
- The image above belongs to editable Technical Sheets for conducting an Energy Audit in a building … HERE. (Very interesting)
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Article prepared by José Luis Morote Salmeron.Access to its website HERE, in collaboration withOVACEN.
