Transcript Optimization Of Net Zero Energy Houses

Section 9.36 of the NBC
Compliance – Three Options
1. Prescriptive Approach
2. Performance Approach
3. Simple Trade-Off Method
(STOM)
Compliance With 9.36 – Three Options
1. Prescriptive Approach
- Use prescribed RSI values and equipment performance
requirements listed in Section 9.36.
- Advantages: easy to use, acceptance by code authorities.
- Disadvantage: lack of flexibility.
Compliance With 9.36 – Three Options
2. Performance Approach
- Model house and verify that its annual energy use does not
exceed that of an equivalent structure designed to 9.36.
- Advantages: very flexible, virtually any type of house or
design detail can be modeled.
- Disadvantages: Time and cost plus availability of trained
personnel.
2. Performance Approach (con’t)
● Intended for situations where major departures from the prescriptive
requirements are planned, and which can not be accommodated with
the STOM.
● Using HOT2000, or an equivalent computer model, the house’s energy
performance is modeled under two conditions:
a) Designed to the prescriptive requirements
b) Designed as is
● The energy consumption of House b) can not exceed that of House a).
● Default values for the house’s operating conditions (temperatures,
occupancies, mechanical ventilation rates, base loads, etc.) are strictly
controlled.
Compliance With 9.36 – Three Options
3. Simple Trade-Off Method
- Use higher-than-required RSI values in one building
component and lower-than-required RSI values in
another component (e.g. trade between walls and attics).
- Advantage: relatively quick and easy to use.
- Disadvantage: Acceptance by code authorities, technical
issues with truss attics.
Simple Trade-Off Method
Opaque-to-Opaque Trades
- Example: Reduce wall RSI level and increase attic RSI
level.
Opaque-to-Transparent Trades
- Example: Reduce window RSI level and increase attic
RSI level.
Opaque-to-Transparent Trades
- Intended for factory-constructed buildings.
- Example: Reduce window area and reduce attic RSI level
How Reality and the Simple Trade-Off
Method View An Attic Trade
Cost Impact Of Section 9.36
● Incremental costs of complying with 9.36 will be estimated.
● However, the provisions are not required to meet any
cost-effectiveness requirement.
● The new 9.36 requirements were established to meet a
pre-defined ERS target – not on the basis of some
economic metric.
Cost Impact Of Section 9.36 (con’t)
● Incremental Cost of an Energy Conservation Measure
= (Unit cost) x (Area or number) x (Utilization Factor)
● For example: The incremental cost of upgrading exterior
wall insulation in Toronto from RSI 2.93 (R-20 nominal) to
RSI 3.30 (R-24 actual) is:
= ($2.14 /m2) x (133.5 m2) x (1)
= $285
Cost Impact Of Section 9.36 (con’t)
● Incremental Cost of an Energy Conservation Measure
= (Unit cost) x (Area or number) x (Utilization Factor)
● For example: The incremental cost of upgrading the
airtightness of a house in Toronto:
= ($2116/house) x (1) x (0.17)
= $360
Costing Airtightness – The Problem
● 9.36 will contain approx. 10 prescriptive details for sealing the
envelope. Total cost of all 10 measures ranges from $2000 to
$3000.
● 9.36 is predicated on an airtightness of 2.5 ac/hr50.
● But, recent NRCan studies have shown that the average
airtightness of new, non-program houses ranges from 2.3 to over
6 ac/hr50, depending on location.
● So, how much will the 9.36 measures add to the cost of the
house?
Costing Airtightness – The Solution
● Using the location’s average airtightness, costs were prorated
based on how much the airtightness has to be improved from the
existing value to 2.5 ac/hr50.
● Results: Estimated costs to upgrade from existing practice
to 2.5 ac/hr50
Vancouver
$ 652
Toronto
$ 360
Montreal
$ 292
Winnipeg
$
0
Fort McMurray
$ 498
Yellowknife
$ 2900
Preliminary Building Envelope Costs
● Using this approach, the preliminary estimated incremental costs
of upgrading to the proposed 9.36 requirements are:
Vancouver
Toronto
Montreal
Winnipeg
Fort McMurray
Yellowknife
$ 951
$ 1068
$ 1001
$ 1394
$ 1942
$ 9229
Any More Questions??