| Summary: | The 1984 Auditor Genera1's report on energy~thrift in the
Health Service claimed that
energy~thrift programmes in
hospitals were not achieving their performance targets.
In order to determine the reasons for this failure,
twenty hospital energy~audits were analysed. It was
discovered that the two principle factors impairing the
performance werez-
(a) The thermal conflict between thrift measures
implemented on the same thermal system, and,
(b) inefficient
implementation strategies.
In order to
investigate the influences of thermal
conflict and
implementation strategy on the out~comes of
energy~thrift programmes,four objectives were defined:~
(i) To
develop a computer model which was capable of
simultaneously thermally modelling the
implementation of energy-thrift measures on
several hospital sites.
(ii) To use the model to predict the thermal and
financial out~comes of various implementation
strategies.
(iii) To test the
sensitivity of the outrcomes to
changes of unit fuel prices and capital costs,
and,
(iv) to compare the predicted results with those
actually obtained.
Data from four hospital sites and ninety thrift measures
were entered into the model for analysis.
It was deduced that a law of diminishing returns existed
between capital investment and annual savings and that
thermal conflict was
responsible for an average annual
financial loss of 15.5%. The financial returns on the
capital invested were considerably enhanced (in one case
by 3ÖØ%) by spreading the financial resources over all
four sites rather than by concentrating the same capital
outlay on a single site. Furthermore it was discovered
that there was a level of capital investment that yielded
an optimal net present value over the selected project
life. The
programmes were more sensitive to reductions
of unit fuel
prices than increases of capital costs.
Most of the
thrift programmes remained viable (N.B.
N.P.V. > Ø
using the public sector discount rate _of 5%
and a project life of 5 years) after the unit fuel prices
had been reduced by 5Ø% of their 1985 levels.
When the results of the implemented programmes were
compared with the models' predictions, the accuracy of
the estimated
savings ranged from a 4.5% under-estimate t
2.5% over-estimate. The
software was designed to find
the best-fit Ventilation rate and`base
temperature for
each
hospital site and for each thermal zone within the
hospital. When the post-implementation assessments of
overall
air-change rate and site base temperature were
compared with those predicted, the model detected changes
closely matching the predictions. â
The results indicated that the technique developed in
this thesis has
potential as a monitoring and targeting
system as well as a thermal model for predicting the out-
comes of
energy-thrift programmes.
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