Reducing the Energy Consumption of Existing Residential Buildings, for Climate Change and Scarce Resource Scenarios in 2050

Abstract

A pilot study of energy efficiency measures, or retrofit actions, was carried out for a single-story detached (single-family) house. It used climate downscaling to project the climatic conditions of a region, and building simulation techniques with two thermal comfort approaches for scenarios of “Climate Change” and “Scarce Resources” in the year 2050. This study was the first stage of a research program to find cost-effective retrofit actions to lower greenhouse gas (GHG) emissions for existing Australian houses in a temperate climate. The pilot study ranked retrofit actions that were cost-effective in reducing the heating and cooling energy usage of a house. These actions included removing carpet from a concrete floor for added thermal mass, and adding external shading with deciduous trees to lower summer radiation from the northern windows (in the southern hemisphere). Also, the alternative thermal comfort approach showed that occupants had more control to lower their energy usage than the standard Australian approach.

Annex 1: Future Climate Morphing Calculation

The main weather parameters of temperature, humidity, radiation, and wind speed are projected for Adelaide for 2050 using Belcher’s morphing approach (Belcher et al. 2005). It creates an RMY set of annual hourly weather parameters for 2050 based on an Adelaide 1990 RMY set of parameters, and the monthly changes in parameters from 1990 to 2050 of the INM-CM3.0 climate model (Clarke and Ricketts 2010).

$$ T = T_{0} + \varDelta T_{m} + \alpha_{Tm} \left( {T_{0} - \bar{T}_{0m} } \right) $$

(1)

$$ {\text{where}}\;\alpha_{Tm} = \frac{{\varDelta T_{MAXm} - \varDelta T_{MINm} }}{{\bar{T}_{0MAXm} - \bar{T}_{0MINm} }} $$

(2)

$$ RH = RH_{0} \left( {1 + \alpha_{RHm} } \right) $$

(3)

$$ I = I_{0} \left( {1 + \alpha_{Im} } \right) $$

(4)

$$ WS = WS_{0} \left( {1 + \alpha_{WSm} } \right) $$

(5)

where

• T and T ₀ are the future and present hourly ambient dry-bulb temperatures, respectively,

• $\bar{T}_{0m} ,\bar{T}_{{0MAX\text{m} }}$and $\bar{T}_{{0MIN\text{m} }}$are the monthly mean values of the ambient dry-bulb temperature, the daily maximum temperature and the daily minimum temperature, respectively, for hourly values calculated over all the averaging years to make up the baseline climate. In this case, the RMY set of one year hourly temperatures represents that base 1990 climate,

• $\varDelta T_{m} ,$ $\varDelta T_{{MAX\text{m} }}$and $\varDelta T_{{MIN\text{m} }}$are the changes projected for each month by the AO-GCMs for the mean temperature, daily maximum temperature and the daily minimum temperature of the dry-bulb temperature, respectively,

• RH and RH _o are the future and the present-day values of the relative humidity, respectively and $\alpha_{RHm}$is the AO-GCM projected fractional change in the monthly mean relative humidity,

• I and I _o denote the future and the present-day solar irradiance and $\alpha_{Im}$ represents the AO-GCM projected fractional change in the monthly mean solar irradiance,

• WS and WS _o are the future and the present-day wind speeds respectively and $\alpha_{WSm}$ is the AO-GCM projected fractional change in the monthly mean wind speed.