PHPP IP - Course III - 11 - Primary Energy

2021

Up and Running with the Passive House Planning Package (9.7 IP) Module 3 | Class 3 | Results

ANNUAL HEAT DEMAND (energy)

NYPH: Up and Running with PHPP

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2021

Q: How do you calculate the winter heating energy demand?

A: QH = (QT + QV) - η

(QS + QI)

Solar + Internal GAINS

Transmission + Ventilation LOSSES Utilization Factor

bldgtyp | NYPH

Q T (Transmission Losses)

Q V (Ventilation Losses)

Q S (Solar Gain)

Q I (Internal Gain)

Q H (Winter Heating Energy Demand) bldgtyp | NYPH

NYPH: Up and Running with PHPP

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2021

Note: To try and make the PHPP better align to North American conventions, they are showing Heating Degree DAYS in this output. Confusingly though, that is not how the math actually works…

QT-srfc = Areasrfc

U-Valuesrfc

ft

Gt-winter

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QV = VV

nv

CAIR

Gt-winter

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NYPH: Up and Running with PHPP

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2021

QS = r

SHGC

Awin.

G

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QI = 0.024

Ht

qi

ATFA

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NYPH: Up and Running with PHPP

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2021

Total Losses Total Useful Gains

Heating Energy Need (Demand)

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Non-Useful Gains

Transmission Losses

Solar Gains Walls Roofs

Floors

Internal Gains

Windows

Heating Energy Needed to balance out the losses Ventilation Losses

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NYPH: Up and Running with PHPP

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2021

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PEAK HEATING LOAD (power)

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2021

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Peak Loads for Heat Pump Systems

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2021

Q: How do you calculate the PEAK winter heating load?

A: PH = (PT + PV)

Transmission + Ventilation LOSSES

(PS + PI)

Solar + Internal GAINS

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Solar Gain?

Image: Copyright Royce L. Bair MMX

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NYPH: Up and Running with PHPP

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2021

7

od el P re di ct

5

ed Lo ad

4

(n o so la

3

r)

Daily Mean Specific Heat Load (W/m 2 )

M

6

2 1 0 -15C

-10C

-5C

-0C 5C Outdoor Air Temperature

10C

15C

20C

15C

20C

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7

od el P re di ct

5

ed Lo ad

4

(n o so la

3

r)

Daily Mean Specific Heat Load (W/m 2 )

M

?

6

2 1 0 -15C

-10C

-5C

-0C 5C Outdoor Air Temperature

10C

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NYPH: Up and Running with PHPP

9

2021

#1 Clear and Cold

#2 Mild and Cloudy

1. Internal Gains ‘Specific Power’ value is lower (assumes building is NOT fully occupied) 2. Heat losses through ‘shared’ party-walls are taken into account (assumes neighbors are away) 3. Increases the envelope air leakage rate (assumes its more windy than normal) bldgtyp | NYPH

P T (Transmission Losses)

P V (Ventilation Losses)

P S (Solar Gain)

P I (Internal Gain)

P H (Peak Heating Load)

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NYPH: Up and Running with PHPP

10

2021

Supply Air Heating?

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•

If the Peak Heat Load is reduced to a very low level (< 3 Btu/hr-ft²) then the heating energy needed can be delivered to the space through the fresh air supply system alone (ERV/HRV)

•

In this case, there is no need for a traditional system (boiler/furnace) which can equal substantial cost savings

•

Air ducts serve two purposes at once: 1) fresh air ventilation and 2) heating supply

But – there’s a problem in some climates: •

The ventilation supply flow rate is typically not sufficient to adequately dehumidify in mixed or hothumid climates, therefor a separate mechanical and duct system for the cooling may still be needed even if supply-air heating is possible.

•

In many North American regions, the winter is not very long but can be very intense (very cold temps). Hitting such a low Peak Load in these climates can be very challenging.

bldgtyp | NYPH

NYPH: Up and Running with PHPP

11

2021

32

68

F

F Extract Air from Int.

Intake Air Post Heater Exhaust Air

Supply Air to Int. 40

F

63

F

120

F Temperature sensor for thermostat mode in suitable reference room

Controller

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Ti

Graphic: Passive House Institute

PRIMARY ENERGY

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12

2021

losses

losses

Energy Demand “End Energy”

Site Energy “Final Energy”

Source Energy “Primary Energy”

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Q: How do you calculate the total Primary (Source) Energy Demand?

A: PE = ( Heating Energy

Heating Fuel Factor ) +

( Cooling Energy

Cooling Fuel Factor ) +

( DHW Energy ( Household Energy

DHW Fuel Factor ) + Household Fuel Factor(s) )

bldgtyp | NYPH

NYPH: Up and Running with PHPP

13

2021

PER < 19.0 kBtu/ft2-yr

PER < 14.3 kBtu/ft2-yr + > 19 kBtu/ft2-yr Renewable Energy

PER < 9.5 kBtu/ft2-yr + > 38 kBtu/ft2-yr Renewable Energy

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NYPH: Up and Running with PHPP

14

2021

Surplus

Shortfall

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Graphic: Passive House Institute

Stuttgart Building Consumption

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Graphic: Passive House Institute

15

2021

Abu Dhabi

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Graphic: Passive House Institute

Losses

DIRECT USE Short Term Storage

Losses

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NYPH: Up and Running with PHPP

Graphic: Passive House Institute

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2021

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NYPH: Up and Running with PHPP

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