Useful paper, Thank you Heba

Dear Mr.Maysam Molana,

its not that quite that simple, ofcourse it depends what kind of a building it is (Residential or normal consumer ) in both cases you should devide a building or a house into small zones also taking into account the appliences as well as the time usually energy consumption of a house hold is in KWh so indeed you have to convert different unites. i am attaching a link and pdf maybe be it will help. cheers

http://www.oru.com/energyandsafety/thepowerofgreen/calculatingenergyuse.html

 Useful links and comment, dear Muhammad,

Thank you so much.

Dear  Maysam,

Yes,  I think you should convert into single energy reference unit if going to make a baseline. You should also take into account the conversion rate of energy conversion due to inefficiency  of energy conversion proses as example burning coal to get electricity. Usually, we will convert energy unit  into CO2e weight factor when referring to the GHG emission.

There are few units of  energy that you can work with in such BTU, calorie (cal), electronvolt (eV), erg, foot-pound,  joule (J),  nutrition calorie (Cal), ton of TNT (tn), watt hour (Wh) but depends to what is your baseline and for what purpose.

In case of chilled water I am not sure what will for your case. Usually the unit will 3.517 kWh for each Ton of cooling (which incidentally contains 12,000 Btu’s.

rgds.

Dear Mohd,

Thank you for your comment, great colleague.

You have rightly said you need to convert all the energy bills to one unit preferably to kW. You need to be careful while doing the unit conversions because this area is prone to error.

Regards,

Manoj

Usually each utility company has its own charging policy. For example electric consumption is measured and charged as kW hour. Gas is measured and charged as per cubic meter consunption. Water has nothing to do with energy is charged as quantity consumed in gallons or cubic meters. You better depend on your meters readings every period of time and then calculate your consumption of each quantity separately.

Regards

Dear Heab,

Interesting comment!

I am encountering to a real case and having all of the energy bills.

Guide me, please

Thanks a lot dear Heba

Useful paper, Thank you Heba

it is not that simple to combine the energy with water. I suggest you to convert cubic meter of gas into kWh and combined it with electricity. Keep the water as it is, i.e. at the end you can say: the total enery consumption is XXX kWh (electecity and gas) and xx m3 of water.

Depends if you want to look at site energy (what you read from the meter), or source energy (which takes into consideration how much energy it takes to produce and deliver a unit of energy to the building). Source energy is a better indicator of environmental impact. So, if you are interested in site energy then just convert M3 of gas to kWh equivalent (conversion calculators are readily available on line, just do a Google search). Then add the electricity and gas. Also, if you can find the energy it takes to produce, collect, and deliver water to the building......then convert that to common units and add to get the total. For Source you have to find the source to site conversion factors for your region. In the US the factor for electricity is between 3 and 4 to 1. For gas the factor is about 1.2 to 1. There are also many common normalizations used to compare buildings such as kWh/M3 (normalizes for building size), or kWh/M3/Degree-Day (normalizes for building size and climate).

Dear Judkoff,

Thank you very much. your comment was so useful.

Please have a look at the attachment. 

Dear Maysam

A simple search on '"conversion table of energy units" will provide you with a lot of results such as a very liable one :www.iea.org/interenerstat_v2/energy_unit.asp.

However, depending on the buildings size, preferably use the most convenient energy unit. For example, kWh is fine for single homes while TOE is better for larger buildings i.e. multifamily or commercisl ones (1 TOE = 11 630 kWh).

Concerning natural gas units, in my country the supplier is expected to give each user the energy equivalent per m3 (last month, my own supplier gives it as 11.33179 kWh/m3. Warning : it may vary depending on the nat gas origin) 

Finally, in order to evaluate the energy contents in 1 m3 of water, I remember some measurements I did at a workplace where water was extracted and delivered in-situ. As far as my own memory is yet correct the number we used was about 1kWh/m3 (if possible, doublecheck  that figure and, please, let me know your own data)

Best regards 

Jacques

Dear Maysam

The bill should be normalized to determine the monthly energy consumption by building. To normalize, there are apps ready

Dear Hamed Moslehi,

Thank you so much for your useful comment and message.

I am so eager to have a nice cooperation in this field.

Dear Maysam

I'm glad to help you

Hi Maysam

Accurate calculations require efficient softwares that conform to 19th principal of national building regulations (conservation of energy consumption).

TABESH software has been developed with the aim of integrating the calculations and control of mechanical installations of buildings and has been approved by Iran's Energy Conservation Organization and the Iranian Energy Efficiency Organization (SABA).

You can use the trial version of the software at the following address:

http://www.tabeshco.ir/assets/Setup.zip

Dear Maysam,

It depends on the purpose you want to calculate it for. Ideally, these all should be calculated and combined in the same unit, it will enhance the adaptability, impact, and comparability of the study. For example, for energy management and the performance indication such as the associated carbon emissions. The methods mentioned above by the forum users are quite relevant and straightforward.

One of the appropriate ways, in my view, is to calculate it in kWh (units) such as using energy/utility invoices and dealing with them accordingly. For electricity it will be quite straightforward however for conversion of gas (i.e. cubic feet/metre) you would need to use kWh conversion formula. You can google it and you will find it for example on British Gas website. Utilising the formula you will input calorific value for gas (generally between 38-40 in the UK) and some constant factors to convert it in to kWh. This can be more effective than using the general conversion factors and can have visible cost/consumption/emission differences/impact at higher demands. Similarly, you can apply it on other types of fossil fuels LPG/LNG. If you wish to add on energy/carbon emissions associated with water use, you could use your national energy/carbon indicators/factors for water treatment and supply. For example, I can vaguely remember that I had studied somewhere that 0.5kWh are required to treat 1cubic meter of wastewater. If your national indicator/s is not available you could use the best available method approach such as these are made available by the UK’s Defra (Department for Environment, Food, and Rural Affairs). Once you have all of these energy/utility streams calculated in kWh or kgCO2, you can translate and associate them according to your objective/s.

The unit of the natural gas consumption is in cubic meter standard conditions one atmospheric pressure and room temperature of 27 degree centigrade.

The consumption of the electricity is in kwh. The water is not energy but there is energy spent in it to filter it and deliver it to homes.

So, the water must be excluded from the energy calcualtions.

It remains the other supplies the gas and the electricity.

You can use a formula like to calculate total energy consumption as :

Total energy consumption= E kwh+ G C m^3= T kwh,

E is the number of the kwhs of electricity, G the gas consumption in cubic meter, C is the conversion factor of one cubic meter gas in kwhs and T is the total equivalent consumption in kwh.

Best wishes

Calculating the total energy consumption of a building is very complicated because there are different types of energy used. In addition, it depends on the purpose of the building, its geographical location, the cultural habits of the users, among many other factors. These papers may be useful:

• A new approach to calculate the energy saving per unit area and emission per person in exterior wall of building using different insulation materials and air gap | [Bina diş duvarlarinda farkli yalitim malzemesi ve hava boşluǧu kullaniminin, birim alandaki enerji tasarrufu ve kişi başi emisyon hesaplamalarinda yeni bir yaklaşim]

• Methodology to calculate the energy consumption for lighting in buildings.

• Creation of a new equation of motion to calculate dissipated energy between two Adjacent Buildings (Compdyn 2015).

• A thermodynamic method to calculate energy & exergy consumption and CO2 emission of building materials based on economic indicator.

• Using time variant voltage to calculate energy and power consumption of building systems.

• Use TBEC software to calculate and analyze the building energy conservation.