"""
Vapor-compressor chiller
"""
from __future__ import division
__author__ = "Thuy-An Nguyen"
__copyright__ = "Copyright 2015, Architecture and Building Systems - ETH Zurich"
__credits__ = ["Thuy-An Nguyen", "Tim Vollrath", "Jimeno A. Fonseca"]
__license__ = "MIT"
__version__ = "0.1"
__maintainer__ = "Daren Thomas"
__email__ = "cea@arch.ethz.ch"
__status__ = "Production"
# technical model
[docs]def calc_VCC(mdot, tsup, tret, gV):
"""
For the operation of a Vapor-compressor chiller between a district cooling network and a condenser with fresh water
to a cooling tower following [D.J. Swider, 2003]_.
:type mdot : float
:param mdot: plant supply mass flow rate to the district cooling network
:type tsup : float
:param tsup: plant supply temperature to DCN
:type tret : float
:param tret: plant return temperature from DCN
:param gV: globalvar.py
:rtype wdot : float
:returns wdot: chiller electric power requirement
:rtype qhotdot : float
:returns qhotdot: condenser heat rejection
..[D.J. Swider, 2003] D.J. Swider (2003). A comparison of empirically based steady-state models for
vapor-compression liquid chillers. Applied Thermal Engineering.
"""
qcolddot = mdot * gV.cp * (tret - tsup) # required cooling at the chiller evaporator
tcoolin = gV.VCC_tcoolin # condenser water inlet temperature in [K]
if qcolddot == 0:
wdot = 0
else:
#Tim Change:
#COP = (tret / tcoolin - 0.0201E-3 * qcolddot / tcoolin) \
# (0.1980E3 * tret / qcolddot + 168.1846E3 * (tcoolin - tret) / (tcoolin * qcolddot) \
# + 0.0201E-3 * qcolddot / tcoolin + 1 - tret / tcoolin)
A = 0.0201E-3 * qcolddot / tcoolin
B = tret / tcoolin
C = 0.1980E3 * tret / qcolddot + 168.1846E3 * (tcoolin - tret) / (tcoolin * qcolddot)
COP = 1 /( (1+C) / (B-A) -1 )
wdot = qcolddot / COP
qhotdot = wdot + qcolddot
return wdot, qhotdot
# Investment costs
[docs]def calc_Cinv_VCC(qcold, gV):
"""
Annualized investment costs for the vapor compressor chiller
:type qcold : float
:param qcold: peak cooling demand in [W]
:param gV: globalvar.py
:returns InvCa: annualized chiller investment cost in CHF/a
:rtype InvCa: float
"""
InvCa = 0.65 * 23E6 * gV.USD_TO_CHF * qcold / 37E6 / 25
return InvCa