Environmental Engineering Reference
In-Depth Information
Water hotter than necessary produces much more moisture and has a high
ecological cost.
With careful bathroom design and bathing practice, the production of dampness
and the diffi culty of restoring a normal level of humidity can be minimised. This
will increase the life of bathroom structure, fi ttings and decoration and preserve
a healthy indoor environment. A quick wipe and wring on the wettest surfaces
are easy and useful. The growth of mould is an important factor which depends
strongly on the length of time that damp conditions prevail and can be avoided.
Drying oneself can be done with a shake and wipe and wring with washcloth,
followed by drying with a small towel. This sends most of the dampness straight
down a plughole as water and leaves very little dampness to be evaporated.
Wet rooms are ecologically a bad idea as well as dangerously slippery.
6.3
CO
2
e
In order to compare the greenhouse contributions of various kinds of bathing, we
need conversion factors from energy to CO
2
e for the different kinds of domestic
energy. This section presents a simple summary of those factors. Greenhouse gas
(GHG) emissions are usually measured in terms of mass of carbon dioxide equiva-
lent (kgCO
2
e, or an SI multiple thereof), that is, of the mass of carbon dioxide (CO
2
,
nowadays often informally written as CO2) that would have the same greenhouse
effect as the mixture of GHGs under consideration. CO
2
is the principal GHG on
account of the huge mass of it emitted which more than compensates for the great
potency per unit of mass of other GHGs.
Energy to CO
2
e Conversion Factors
I have taken the factors displayed in
Table
7.2
from Defra/DECC (
2012
). The electricity fi gure is from Annex 3 and the
others from Annex 1. In Annex 1 I have taken the fi gures for 'Scope 3', which
include
'
Indirect emissions associated with the extraction and transport of primary
fuels as well as the refi ning, distribution, storage and retail of fi nished fuels.
Emission factors are based on data from the JEC Well-To-Wheels study …'. I have
also selected the 'net CV [calorifi c value] basis'; 'Gross CV or higher heating value
(HHV) is the CV under laboratory conditions. Net CV or lower heating value (LHV)
is the useful calorifi c value in typical real world conditions (e.g. boiler plant). The
difference is essentially the latent heat of the water vapour produced (which can be
recovered in laboratory conditions)'.
Table 7.2
Energy to CO
2
e conversion factors
Consumed
electricity
Coal
(domestic)
Energy source
Natural gas
Fuel oil
Energy to CO
2
e conversion
factor (kgCO
2
e/kWh)
0.59
0.23
0.34
0.41
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