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3. COMPONENT DESCRIPTION
The components in the Absorption cycle operate with LiBr and/or water.
The Absorption cycle can be split up into two sub cycles: a refrigeration
cycle and a solution cycle. The water used in the refrigeration cycle is a
real fluid since the fluid undergo phase transition.
The water-LiBr solution in the solution cycle is also calculated by a
real fluid function ”LiBrH2O”. The function is valid for saturated liquid
only, e.g. the quality qu = 0. Several properties, e.g. pressure and heat
capacity are calculated from input of temperature and the mass fraction
of LiBr, w, which must be in the range of 0 to about 0,75 1 (can be seen in
phase diagram in appendix B.4.1 page 231).
Since the function only work for saturated liquid, just two state
variables are necessary to define the state. The properties for both
refrigerant and the cooling water are determined by the internal EES real
fluid function ”Water”.
General assumptions
All heat flow rates ˙Q and power Ẇ are calculated as positive quantities.
It is assumed that the components don’t leak any fluid to the surroundings:
ṁ o = ṁ i (3.2)
Potential and kinetic energy is neglected for all components. The
energy required to circulate water in the external heat transferring loops
(including domestic hot water) has been neglected as well. The heat
loss from the components to the surroundings is assumed to be zero if
nothing else is stated, but can be given by a heat loss parameter for each
single component.
Wherever it is feasible, the heat exchangers are assumed to be
configured in counterflow.
1 Very dependent on temperature and pressure. The range is valid for the normal
operation of an absorption cycle.
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