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A building has a base temperature of {base_temp}°C. Below is the recorded temperature data for a given day in 6 hour intervals:

\n

00:00 - 06:00 → {temp_1}°C
06:00 - 12:00 → {temp_2}°C
12:00 - 18:00 → {temp_3}°C
18:00 - 00:00 → {temp_4}°C

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Calculate the total heating degree days for the day.

\n

\n

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Using the heating degree day (HDD) formula:

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HDD = (Base Temperature−Outside Temperature)×Time Fraction

\n

\n

HDD = ({base_temp}°C - {temp_1}°C × 6/24) + ({base_temp}°C - {temp_2}°C × 6/24) + ({base_temp}°C - {temp_3}°C × 6/24) + ({base_temp}°C - {temp_4}°C × 6/24)

\n

\n

HDD = ({base_temp - temp_1}°C × 0.25) + ({base_temp - temp_2}°C × 0.25) + ({base_temp - temp_3}°C × 0.25) + ({base_temp - temp_4}°C × 0.25)

\n

\n

Remember to not include temperatures that exceed our base temperature.

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HDD = ({dd1/0.25} × 0.25) + ({dd2/0.25} × 0.25) + ({dd3/0.25} × 0.25) + ({dd4/0.25} × 0.25)

\n

HDD = {dd1} + {dd2} + {dd3} + {dd4}

\n

HDD = {dd1+dd2+dd3+dd4}

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Temperature for the first 6 hour period

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The building's base temperature

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Degree day for the 6 hour period.

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Variable to store the total heating degree days for the entire period

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Dan, the facilities manager, is under pressure to prove that his investment in insulation has led to significant energy savings. The heating energy consumption and heating degree days (HDD) for two consecutive years are as follows:

\n\n

Dan needs to determine the energy efficiency improvement by calculating the kWh per degree day for each year and then finding the percentage change.

\n

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kWh per degree day in 2023:

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{heating_energy_pre}kWh / {hdd_pre} = {energy_degree_day_pre}

\n

kWh per degree day in 2024:

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{heating_energy_post}kWh / {hdd_post} = {energy_degree_day_post}

\n

Percentage improvement:

\n

({energy_degree_day_pre} - {energy_degree_day_post}) / {energy_degree_day_pre} × 100 = {improvement}%

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Building heating energy consumption before insulation, in kWh

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Building heating energy consumption after insulation, in kWh

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Heating degree days in the year before insulation. 

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Heating degree days in the year after insulation. 

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Energy usage per degree day before insulation.

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Energy usage per degree day after insulation.

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Percentage improvement between years 

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Calculate the kWh per degree day for 2023.

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Calculate the kWh per degree day for 2024.

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Determine the percentage improvement in energy efficiency from 2023 to 2024.

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