University:
Conestoga College
Course:
ERGY8070 | Energy, Storage and Management
Academic year:

2021
Views:

150

Pages:

3
Author:

S T Cherukuri

Week 9 ERGY8070 1. The average daily outdoor temperature is 34ºC; how many cooling degree days are there (base temperature 18ºC) for this day? 2. The average daily outdoor temperature is -10ºC; how many heating degree days are there (base temperature 18ºC) for this day? 3. The average daily outdoor temperature is 7ºC; how many cooling degree days are there (base temperature 10ºC) for this day? 4. What is the energy usage intensity (EUI) in equivalent kilowatt hours (ekWh) per part for a factory that produces 2,500,000 parts annually and consumes 6,250,000 kWh of electricity and 250,000 m3 of natural gas? 5. The following regression model is used to calculate daily electricity consumption for a gas-heated office building: Daily kWh = (647 x CDD14ºC) + 38,118 a) What part of this equation could be considered the baseload of the building? b) What is the daily energy use for a day with an average outdoor temperature of 18ºC? 6. What is the EUI of a 110,000 ft2 building that consumes 975,000 kWh of electricity and 87,250 m3 of natural gas annually? Week 9 ERGY8070 ANSWERS 1. The average daily outdoor temperature is 34ºC; how many cooling degree days are there (base temperature 18ºC) for this day? Daily CDD = Average Daily Temperature – Base Temperate = 34 – 18 = 16 2. The average daily outdoor temperature is -10ºC; how many heating degree days are there (base temperature 18ºC) for this day? Daily HDD = Base Temperature - Average Daily Temperature = 18 – (-10) = 28 3. The average daily outdoor temperature is 7ºC; how many cooling degree days are there (base temperature 10ºC) for this day? Daily CDD = Average Daily Temperature – Base Temperate = 7 – 10 = (-3) Please note that negative CDD and HDD are not possible. Therefore, the daily CDD is 0. 4. What is the energy usage intensity (EUI) in equivalent kilowatt hours (ekWh) per part for a factory that produces 2,500,000 parts annually and consumes 6,250,000 kWh of electricity and 250,000 m3 of natural gas? EUI = Annual Energy Consumption / Annual Production EUI = (6,250,000 kWh + [250,000 m3 x 10.5 kWh/m3]) / 2,500,000 parts = 3.55 ekWh/part 5. The following regression model is used to calculate daily electricity consumption for a gas-heated office building: Daily kWh = (647 x CDD14ºC) + 38,118 What part of this equation could be considered the baseload of the building? a) In the above equation 38,118 kWh can be considered the daily “baseload” energy. In this context, “baseload” refers to the total non-weather-dependent daily energy consumption. This differs from other uses of the term “baseload” which can also refer to the energy / power of equipment that is always on. b) Daily CDD = 18 – 14 = 4; Daily kWh = (647 x 4) + 38,118 = 40,706 Week 9 ERGY8070 6. What is the EUI of a 100,000 ft2 building that consumes 975,000 kWh of electricity and 87,250 m3 of natural gas annually? EUI (ekWh/ft2) = [Gas kWh + Electricity kWh] / Building Area in ft2 EUI =[ (12,750 m3 * 10.5 kWh/m3) + 975,000 kWh] / 110,000 ft2 EUI = 17.2 ekWh / ft2