Solar Optimisation and Customer Behaviour
Expansion Vessel Sizing
The previous pages have examined the arrangement of the various components, collector,
store, pump and controller, into a safe and potentially efficient system for collecting
and storing solar heat. The potential of these systems will only be realised if they
are properly coupled to the auxiliary heating and controlled sympatheticaly by the householder.
Increasing the Solar Provision
To maximise the utilisation of solar hot water, as much of the household demand must be
supplied from the stored hot water. To achieve the oft quoted 60% of the total hot water
from solar energy requires some thought not just in the use of water in baths and showers
but also in appliances and even at an earlier stage in the location of the hot water
storage cylider and the insulation of distribution pipework.
There can be a tendency in househlds that have installed solar hot water systems to
increase their hot water consumption under the misapprehension that all the hot water
is 'for free.' Excessive consumption will require increase the use of the auxiliary
heating system possibly during the solar heating season and on into the rest of the
year if altered consumption patterns are maintained. Auxiliary fuel bills may even
show little or much lower than expected falls and payback times for the installations
will be extended. Other drivers are encouraging reduced water consumption through
water conservation and reduced energy use for hot water provision. In England and
Wales the Code for Sustainable Homes rewards the use of measures to reduce such consumption.