We are working on the certification of a building that will be connected to a DES using a CHP plant. The DES delivers to the building chilled and hot water for cooling, heating and DHW.
The DES has a cogeneration biomass plant (residue from city parks). The electricity produced is directly used into the DES. Actually the cogeneration system produces 3 times the whole electricity consumed by the plant, including chillers and circulation pumps consumption.
The thermal output of the cogeneration biomass plant is used within the DES to enhance the efficiency of the gas boilers that deliver hot water to the buildings.
The question is: do we have to follow the Appendix D of the 'Treatment of District or Campus Thermal Energy in LEED' guide?
From this guide and also from what is said in the reference guide EAc1 CASES 3 and 4. District CHP it seems that the electricity allocation for the building is related with the thermal output of the CHP. I think this would be restrictive in our case as the electricity output of the CHP covers all electricity needs of the DES plant.
We would appreciate any thought on this situation!
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5912 thumbs up
January 26, 2016 - 10:55 am
Where is the project located?
Emmanuel Pauwels
OwnerGreen Living Projects
137 thumbs up
January 26, 2016 - 11:02 am
The project is in Spain, Barcelona
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5912 thumbs up
January 26, 2016 - 5:15 pm
You are not required to follow that guidance as you can always use DESv2 Option 1 or 90.1-2007 Addendum ai. You will need to use some type of guidance to model your situation. Another option is this for European projects.
http://www.usgbc.org/resources/treatment-scandinavian-district-energy-sy...
Emmanuel Pauwels
OwnerGreen Living Projects
137 thumbs up
January 29, 2016 - 10:05 am
Marcus, thanks for your guidance. Instead of DESv2 Option 1, we are looking into DESv2 Option 2 in order to account for DES actual efficiencies. The DES we will be connected to includes a cogeneration plant producing heat, cold and electricity. The input energy of the DES is biomass and gas. The DES provides hot and cold water to its network of customers. The net electricity they produce is not sold to their customers but to a utility company.
The cogeneration plant consumes 28 units of biomass to produce 12 units of electricity and 9 units of heat. 4 units of electricity are consumed by the DES itself (for chillers to produce cold water and distribution pumps). The 8 remaining units of electricity are sold to the utility company. The heat is complemented with additional heat generated by a gas boiler using 4 units of gas and distributed as hot water to the clients. The DES distributes 12 units of hot water and 8 units of cold water to their clients.
We would like to use Option 2 of the DES guidelines. For this situation, the baseline would be modelled as per Appendix G with electricity for cooling and gas for heating.
According to the Option 2, DES guidelines, the proposed case will have the chillers and boiler of the DES plant and the cost of the produced energy is calculated as follows: cost of biomass divided by the total thermal outputs of the plant (cost of 28 units of biomass + 4 units of gas / (12+8 units of thermal outputs = $/kWh).
If this is correct we are including energy inputs associated with the electricity sold to a third party (the utility). How do we take this into account?
Emmanuel Pauwels
OwnerGreen Living Projects
137 thumbs up
January 29, 2016 - 10:14 am
Marcus, thank you for your guidance. In order to account for actual DES efficiencies, we are looking at DESv2 Option 2. The DES we will be connected to includes a cogeneration plant producing heat, cold and electricity. The input energy of the DES is biomass and gas. The DES provides hot and cold water to its network of customers. The net electricity they produce is not sold to their customers but to a utility company.
The cogeneration plant consumes 28 units of biomass to produce 12 units of electricity and 9 units of heat. 4 units of electricity are consumed by the DES itself (for chillers to produce cold water and distribution pumps). The heat is complemented with additional heat generated by a gas boiler using 4 units of gas and distributed as hot water to the clients. So, with 28 units of biomass and 4 units of gas, the DES distributes 12 units of hot water and 8 units of cold water to their clients while selling 8 units of electricity to the utility company.
According to Option 2 of the DES guidelines, the baseline would be modelled as per Appendix G with electricity for cooling and gas for heating.
For the proposed case, we simulate the chillers and boiler of the DES plant and the cost of the produced energy is calculated as follows: cost of biomass divided by the total thermal outputs of the plant (cost of 28 units of biomass + 4 units of gas / (12+8 units of thermal outputs = $/kWh).
If this is correct we are including energy inputs associated with the electricity sold to a third party (the utility). How do we take this into account?
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5912 thumbs up
January 29, 2016 - 4:25 pm
(cost of 28 units of biomass + 4 units of gas) / (12 units of hot water) = $/kWh of fuel used to produce the hot water in the Proposed model
The 8 units of cold water are modeled as all electricity in the Proposed Case. The electricity produced by the cogen plant gets allocated to the building according to Appendix D of the DESv2. It does not matter how much electricity is used in the plant or sold to the utility.