Abstract:
District-heating and/or cooling systems are gradually becoming
popular all over the world for heating and/or cooling of
large premises.
Current conventional practice for the DHC underground
distribution networks is to place the supply and the return pipelines
side-by-side in air-filled trencRe's. However, t present
investigation has shown that by optimising the location of the
pipelines, the thermal insulation provided by the air around the
pipes can be maximised. This is achieved by placing the hot pipeline
above the cold one, the exact position depending upon the
temperatures involved. For most purposes, it is recommended that
the displacement ratio for the hot pipe is to be at -0.7 or -0.08
and that of the cold pipe at 0.05 or 0.67 for district heating or
cooling respectively [i. e. the hot and cold pipes being placed in
the upper and lower halves of the trench respectively].
Each chapter is presented in such a way that it can be read
independently of the others as far as possible.
