Energy Performance of Buildings ( EPB ) for energy auditors – calculations and tutorials
CALCULATION PROCEDURE for ENERGY PERFORMANCE of BUILDINGS
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Calculation procedure for Energy Performance of Buildings
Text Tutorials – click below
Climate data ( T ext , Solar Intensities )
Text Tutorials – click below
Operating Program & Weighted internal temperatures (Tint) – Heated / Cooled Surface and Volume
Text Tutorials – click below
Calculation of the building Envelope – to the outside , to the Ground and to the Unconditionated spaces
Calculation Coef thermal transfer directly to atmospheric air – Hd (W/K)
Text Tutorials – click below
Calculation Coef thermal transfer through the Soil – Hg (W/K)
Text Tutorials – click below
Calculation Coef thermal transfer through Unconditionated spaces – Hu (W/K)
Text Tutorials – click below
Calculation of specific Energy required for Cooling (kWh/sqm)
Text Tutorials – click below
Calculation of final consumption of Energy for Heating – including Instalation (kWh/sqm)
Text Tutorials – click below
Energy Studies and Reports
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MISCELLANEOUS – Auditors
Text Tutorials
MISCELLANEOUS – Population
Text Tutorials
Calculation procedure for Energy Performance of Buildings
Calculation procedure for Energy Performance of Buildings is a many step procedure , at the end of it we will get :
Specific consumption of FINAL and PRIMARY energy for all 5 utilities than can be in a building : HEATING / COOLING / HOT WATER / VENTILATION / LIGHTING in kWh / sqm,year
Specific release of CO2 and other greenhouse gases in kg CO2 / sqm,year
Specific production of energy from Renewable Sources in kWh / sqm,year.
We have to make a distinction between Energy Consumptions of Buildings and Energy Performance of Buildings . We first calculate energy consumptions and after that we compare those consumptions with a value grid and we conclude in witch energy class they falls .
The grid of valued differs from one country to another.
Climate data
Romania
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USA & Canada
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China
Energy Performance of Buildings (EPB) for energy auditors – calculations and tutorials is a large subject , a part of it is about climatic data . Every country , large or small , has a National Meteorological Institute which collects data and in time , tens of years , creates a climate pattern for different regions of the country.
For towns in that climatic zones the Institute will create meterological data for a standard year , from where auditors can take montly dates : Temperatures , Humidity , Solar Intensities ( depending on orientations ) , etc.
When you have to make an Energy Performace of a building in a specific town , you will take that official data and use in calculations.
The most used time duration for energy performance calculations is MONTHLY . The calculations are made monthly and make a amount of all months for a year.
Even there are some meteorological institutes which created data for a standard year all 365 days * 24 h/day = 8 760 h / year , in general is very complicated to use for calculations methods DAILY or HOURLY because the volume of calculations.
The MOUNTHY method aproximate that all 30 days * 24 h / day = 720 h / month have the same External temperature , the same humidity , solar intensity , etc.
Becouse I will try to aply all the calculations for the whole world , I created a universal climatic map.
It containes 5 climatic zones with temperatures between +6 and +13 deg.C . Those are temperatures present in my country Romania for witch I have detailed climatic data for many cities.
In generaly identical buildings , with identical cardinal points orientations , from cities with the same annual average temperature can be aproximate to have the same energy calculations . It is about final energy not primary energy .
Primary energy = different coefficients * Final energy . Those coefficients differ from contry to country.
Ti - Internal temperature
Energy Performance of Buildings (EPB) for energy auditors – calculations and tutorials is a large subject , a part of is is about tempeature in interior of buiding . Tint = Ti – internal temperature for calculations . We have two methods to calculate Ti , we first use one and with calculated data will use the second method :
Spatial mediation Ti,spatial med.= sum(Ti,conv,n * Vn) / sum(Vn) where :
Ti,conv,n – Conventional temperature of space n / Vn – Volume of space n , Conventional temperatures are taken from Standards , in EU we work with Standard EN 16798-1/NA-2019 . It very important to understand the difference between Ti set by occupants of the building , some will want a higher internal temperature and other a lower one , and the STANDARD internal temperature . We have to work with STANDARD temperatures because we calculate the Energy consumptions of buildings , not the Energy consumptions of the occupants . That it means for example that the Ti for an apartament will be let’s say 20 deg Celcius indifferent if in it lives a family with small childrens and they set the internal temperature at 23 deg Celcius , or in it lives a young couple and they set the internal temperature at 19 deg Celcius. The CALCULATED CONSUMPTIONS for that apartment are a value specific to that apartment indiferent of the preferences of the occupants.
If we do not work with STANDARD internal temperatures that it will mean that we will have a different Certificat of Energy Performace when the apartment is occupied by the family with small childrens and another Certificate of Energy Performance when the apartment is occupied by the young couple.This will be absurde.
After we calculate Ti with spatial mediation with that values we continue with :
Temporal mediation Ti = (Ti,spatial med.,day * Nday + Ti,spatial med.,night * Nnight + Ti,spatial med.,weekend * Nweekend) / 168 where :
Ti,spatial med.,day – internal temperature on day / Nday – number of hours in a week with that temperature
Ti,spatial med.,night – internal temperature on night / Nnight – number of hours in a week with that temperature
Ti,spatial med.,weekend – internal temperature on weekend / Nweekend – number of hours in a week with that temperature
Nday + Nnight + Nweekend = 168 h ( 7 days * 24 h/day )
Su – usefull surface surface from the building of the space heated / cooled
Vu – usefull volume volume of air from the building heated / cooled
About calculation of Coeficient thermal transfer directly to atmospheric air - Hd (W/K)
Hd = Hd walls + Hd terrace + Hd roof directly over + Hd plate protruding over + Hd windows + Hd doors
To obtain liniar thermal bridge coefficients you can use Catalogue of thermal bridges – romanian language
Catalogue of thermal bridges – english language
I also use Catalogue of thermal bridges in romanian language because in translation between romanian -> english , some formula become unclear and you can take them from the romanian version . Also when the translation is not good you can take a phrase from romanian and put it for translation on Google translate for translation in english or your native language.
About calculation of Coeficient thermal transfer through the Soil - Hg (W/K)
In Romania we have a very good Normative for calculating Thermal transfer through the Soil.
It has also thermal bridges coefficients for the elements of anvelope in contact with Soil.
You can download it from : Normative C107/5 – romanian language
Normative C107/5 – english language
The thermal bridges coefficients are at the end of the Normative.
I also use Normative C107/5 in romanian language because in translation between romanian -> english , some formula become unclear and you can take them from the romanian version . Also when the translation is not good you can take a phrase from romanian and put it for translation on Google translate for translation in english or your native language.
Calculation Coefficient thermal transfer through Unconditionated spaces Hu (W/K)
Attic insulation (for more detailed calculations - see video with calculations)
Calculations Tattic , b , Hattic
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Calculation of specific Energy required for Cooling (kWh / sqm)
The calculations , for a medium thermoisolated house in Bucharest,Romania,
begin with the calculation of the cooling period.
External temperature to START / STOP cooling is :
Text cooling (°C) = Tint – (Φi +Φs) / (η1 * H) , where :
Tint(°C) = internal temperature for cooling period ,
Φi (W) – internal flux / Φs (W) – solar flux
η1 – coefficient for cooling
H (W/K) – coupling thermal coefficient of the building
COOLING
After we have the period for cooling we can calculate the final energy required for cooling.In Romania we use monthly calculations,we asume that on a specific month we have for all the 30*24 = 720 hours the same Internal temperature,External temperature,Solar flux,Internal flux.We will calculate every month,by number of days the necesary energy for cooling and the summ of all the cooling months will be the
Final energy for cooling (kWh) – for specific energy we will divide to the Usefull Area of the building (sqm) (you can enlarge the photo from right )
fsh – shadow reduction factor
In the table from the right you can find different shadow reduction factors.They reduce the Solar flux thrue the windows and can have a grate reduction for the period of cooling and for the Final energy for cooling.
DEHUMIDIFICATION
The final energy required for Dehumidification is also calculated every month on the period for cooling.The formula to calculate the energy required for one hour for dehumidification is :
Qdehum (Wh) = N * Occup.rate * Water vapor rel.pers. * hwe * (1-na) where :
N – number of people / Occupancy rate = Ndays occup / N days / Water vapor release / person (g/s,person) / Hwe – latent heat water vaporization (J/g) / na – number of air changes / hour
Water vapors release per person (g/s,person)
There are different sorces of information for the water vapors release per person in buildings.If we add :
the human release,
the cooking and
the bathroom , we get a total.
That total for different types of buildings we will use in the formula for Energy for dehumidification from the above.
Calculations of final consumptions of Energy for Heating and Hot water - including Instalations (kWh / sqm)
Energy Studies and Reports
Different countries have different types of Energy Studies and Reports . Two of them are present in any country :
Energy Performance Certificate , for Romania model you can see , download from : Energy Performance Certificate – Romania
Energy Audit Report for Buildings , for Romania model you can see , download from : Energy Audit Report for Buildings
Also in many countries is another report that checks if a building meets the NZEB conditions , these conditions differ from one contry to another :
NZEB Report , for Romania model you can see , download from : NZEB Report
Also in many countries is another study , that preceds the NZEB Report , in Romania we call it Study of Sources of Renewable Energies in witch we reduce the number of solutions from several hundreds of Renewable Energies solutions to a few to be analize , and propose one depending of GLOBAL COST . In Romania we call that study : Study SRE.
Study SRE , for Romania model you can see , download from : Study SRE
I want to mention that all those studies and reports are GENERATED AUTOMATICALLY by InteliEPB Application . More information about it you can find in page About from this website.
Mix ZTC
Energy Performance of Buildings (EPB) for energy auditors – calculations and tutorials is a large subject , a part of it is about ZTC .
ZTC stands for Thermally Insulated Zones, i.e. areas of the building where, with the help of Heating/Cooling Systems, the occupants of the building decide what temperatures will be in those areas.
ZTU stands for Thermally Unconditioned Zones, i.e. areas of the building where we do not have Heating/Cooling and their interior temperature is naturally achieved by balancing the energy flows that Enter/Exit that area.
For example, the building in the plan below:
We notice that this building has 2 ZTU and 3 ZTC.
ZTC 1 is a store with an operating program of Mon-Sat between 8.00-21.00 that is closed on Sunday. It has heating and hot water with electric HEAT PUMP , with underfloor heating.In the bottom part , partial stay on ground and another part is coupled to the unheated basement ZTU 1.
ZTC 2 is an apartment with an continuous operating program. It has radiant floor heating with thermal agent for heating and hot water from OWN CENTRAL with GAS.
ZTC 3 is a kindergarten with an operating program of Mon-Fri between 9.00-17.00 and is closed on Sat, Sun also during the holidays. It has thermal agent for heating and hot water from OWN CENTRAL with GAS , the heating distribution is made on radiators. In the upper part it is thermally coupled to the unheated attic of the ZTU 2 building.
In Romania , in our Methodology , Mc 001-2022 / Chapter 2.6.2 – Thermal zoning we have the following :
The heated, cooled, air-conditioned areas next to each other can be combined if they have identical or similar thermal conditions of use, namely when the following 2 conditions are simultaneously met:
1. The difference between the temperature settings for heating is less than 4 degrees and the difference between the minimum and maximum moisture content settings is less than 0.2kg/kg dry air
AND
2. Daily operating periods do not differ by more than 3 hours.
These conditions my differ from country to contry but let’s say that the building can’t be seen as a single Thermal zone.
As we can see, these conditions are not met by the 3 ZTCs of our building, so we cannot fit them together and work as a single ZTC.In this case we will work each ZTC as a distinct building, as a envelope we will take only the elements to the outside or to the neighboring ZTUs. We will calculate the specific energy requirement (q – kWh/mp,year) for present utilities, CO2 release (kg CO2/mp,year), renewable primary energies, etc. When we have all the data for the 3 ZTCs we will calculate what is the energy consumed for each utility cumulatively on all 3 ZTCs and we will obtain e.g. (final or primary) for heating a
q,h total = Sum(q,h1*S1 + q,h2*S2 + q,h3*S3) / Sum(S1+S2+S3)
this total q,h is actually the energy consumed for Heating on the entire building,all 3 ZTC / Total heated surfaces for all 3 ZTC.
We will do the same with CO2 releases, renewable primary energy, etc.
An interesting question is why we don’t calculate the Energy Losses / Inputs between the ZTCs. Because they cancel each other out (some are with + and some with – , but exactly the same values) when we add up the Energy on the entire building.
Here is the Table with those calculations :
Number of energy auditors for buildings in different countries
What we will try to find in this study is the number of energy auditors for buildings in Romania , my country , in Europe and to estimate the total number of energy auditors in the whole world.
The “magical” number in every contry is the density of energy auditors from total population , measured in 1 auditor / 10 000 people from a country.
In Romania , in 2024 we have 1 200 auditors at a population of aprox. 19 000 000 people –> a density of 0.6 auditors / 10 000 people.
From what I found on internet , in Germany are aprox. 8 000 auditors at aprox.population of 80 000 000 people –> a density of 1 auditor / 10 000 people. see here
I found also on internet the number of energy auditors in Switzerland witch was in 2020 of 1 529 auditors at an aprox.population of 9 000 000 people –> a density of 1.6 auditors / 10 000 people. see here
The most complete source of information for the number of energy auditors for buildings in different european countries we find in Cap.04.04 here
In that study we see that density of energy auditors in Europa is very variable from 0.4 auditors / 10 000 people in Bulgaria to 44 auditors / 10 000 people in Austria.
To calculate the whole number of energy auditors of buildings in the entire world I propose to use a medium density of 1 auditor / 10 000 people , at a population of 8 000 000 000 people in 2024 . Let’s say that are regions where there are no auditors and we will use a number of 7 000 000 000 people –> the aprox.number of energy auditors for buiding in the whole world = 700 000 auditors.
If we estimate the number of persons from ministries and gouverments ,agencies from all the countries , involved in energy performance of building at aprox. 300 000 people –> a total of 1 000 000 people are directly resposible in the whole word with the reduction of CO2 emision from buildings , witch is aprox. 40% of the whole CO2 emision.
How to have a good energy auditor website that attracts customers
Nowadays we can no longer ignore the internet and carry out our activity as if it did not exist. The best presentation of a company can be made on the INTERNET with the help of a WEBSITE.
With the help of a quality WEBSITE , with qualitative and attractively presented information, we can attract customers to our firm through which we carry out our activity as Energy Auditors.
From discussions with several auditors, but also with other businessmen, I noticed that those over 45 – 50 years old do not realize how big the impact can be on their companies if they have a WEBSITE that appears on the first positions in Search Engine searches (Google, Bing, Firefox, etc.). Usually they treat the WEBSITE to be there, if it goes well if not all good, not realizing that it can change their entire business for the better.
Unfortunately, they generally had unfortunate experiences with the company’s website, that is, they found that they invested quite large amounts in it (in the order of thousands of Euros) but the benefits were small or very small.
As part of you already know, and the rest you can find out on the About page of this site, I am also a Programmer, in addition to being an Energy Auditor gr. I . In general, programmers know several IT areas, for example, in addition to Excel, Java I also know something about the creation of Websites so what I am telling you is in perfect knowledge of the facts. For example, this site you are on now I created myself.
Unfortunately, the programmers who created your websites don’t tell you one ESSENTIAL thing, it’s useless to have a beautiful and apparently professional site if it doesn’t have traffic (number of customers daily or monthly) and DOESN’T APPEAR IN THE TOP 10 POSITIONS WHEN SEARCHING WITH SEARCH ENGINES.
Here is a graph that shows how the number of customers attracted by a website evolves depending on the position in which it is found on the search pages, when certain keywords are entered, for search in Search Engines:
What does the Click Thru Rate that appears on the vertical axis mean: it means how many percent of those who make that search enter the respective website according to its position in the search result by the Search Engine. From now on by Search Engine I will understand Google as it is used in a proportion of 90%.
For example, let’s say that we type in the search words: “energy performance certificates london” and we get a result that spans tens or hundreds of pages of answers from Google.
The first results you will see are those paid for advertising to Google , which are marked separately . In general, according to statistics, people partially avoid them because they realize that those websites are put there, not necessarily because they are good, but because they paid to be there. After these results, the websites that did not pay to Google and were found by the GOOGLE SEARCH ALGORITHM appear. This algorithm is put into operation by software robots called crawlers that scan the Internet 24/7 by continuously searching for Internet pages and collecting a lot of data about their content and how much people are watching.
After this scan of the entire Internet, once every few days, the GOOGLE SEARCH ALGORITHM ranks them according to a large number of criteria, the most important being: The number of views, How long a user stays on them, What links do they have from other sites, etc.
In this way, Google ensures that the most interesting websites for that search are in the top positions.
THE KEY TO A WEBSITE’S USEFULNESS LIES IN HOW WELL IT RANKS ON THE PAGES THAT GOOGLE DISPLAYS.
As you can see in the graphs above, the website in the first position attracts about 35% of those who turned to Google, and the website in the 10th position attracts about 2.5%. So a huge difference, 14 times more potential customers attracts the website from the first position compared to the one on the 10th position. Not to mention attracting customers to a website in the 20th or 30th position.
Now you understand why many have disappointments about these websites, because the programmers who make them “forget” to say these things that they actually know very well. If all the programmers’ beneficiaries knew them, maybe the number of websites would be reduced by 10 times, the ones that are constantly after the 20th position in the search results are made IN VAIN.
This SHOULD NOT DISCOURAGE YOU but just know that you must have some high-performance websites that RANK ON THE TOP 10 POSITIONS. This is an ongoing struggle, somewhat similar to the tennis rankings when a tennis player participates and wins many tournaments to be in the top 10 worldwide.
There’s a subbranch of programming called Search Engine Optimization (SEO) that deals with getting a website up to No. 1 or close.
From all of programmers who can create or maintain a website no more than 2-3% are SEO specialists to bring your website in the top 10 search positions. So you have to be careful how you find one, you can try other website owners to see if they have worked with such a specialist and his work really had results.
The first ones you will turn to will be those who create or maintain your website. Many will tell you that they know SEO and will want to do the job themselves. First ask them to exemplify which websites they have had results with and to put you in touch with their owners, that is, to take References. It is also possible for those programmers to recommend you an SEO specialist.
Get in touch with him , ask as in the previous case References and if everything is Ok get to work with it. When you make a contract with him, it is good to give him part of the money when the work starts and the rest, over 50%, to give him after you see what position the website is in. You can motivate him with a Premium if he brings the website in the top 3 positions.
