19 Purchased Energy & CHP
This action guides the user how to address purchased energy and CHP in the proposed model (as B 8.4.35).
The NECB is energy neutral; unlike other building codes, the NECB does not concern itself with the energy cost and does not give credit or performance gains for using renewable energy, whether it is produced on site or purchased. Similarly, no credit or performance gains can be attributed to a building simply due to fuel switching.
The excessive use of energy is what the code limits so:
· Renewable energy is excluded from the compliance assessment (even if included in the model);
· CHP is considered purchased energy which can be either hot or cold (chilled) water, high or low pressure steam or electricity produced from cogeneration or renewable means.
8.4.3.5. Purchased Energy (also see Note A-8.4.3.5.)
1) Where the proposed building uses purchased energy for space heating or cooling or service water heating, Sentences (2) to (5) shall apply.
2) Where purchased energy is used for heating, the equipment used to provide this energy shall be modelled as a gas-fired modulating boiler that
a) is sized for the peak heating load provided by the purchased energy system, and
b) complies with Section 5.2.
3) Where purchased energy is used for cooling, the equipment used to provide this energy shall be modelled as an electric air-cooled chiller that
a) is sized for the peak cooling load provided by the purchased energy system, and
b) complies with Table 8.4.3.5.
4) Where purchased energy is used for service water heating, the equipment used to provide this energy shall be modeled as a gas-fired service water heater that
a) is sized for the peak heating capacity provided by the purchased energy system,
b) complies with Section 6.2., and
c) where the purchased energy is used to heat service water in a heater with a storage tank, has the same storage capacity.
5) The operating schedule, priority of use and other operational characteristics of the purchased energy shall be included in the energy model.
