The package Buildings.Fluid.SolarCollectors contains models used for simulation of solar thermal systems. Top-level models are available for solar collectors based on the ASHRAE93 and EN12975 test protocols. The two models use different models for solar gain, heat loss and data packages. Solar gain and heat loss models are available for use with data obtained from ASHRAE93 and EN12975 test procedures. Data packages containing default values for several collectors are available in packages for concentrating, flat plate and tubular collectors.
Buildings.Fluid.SolarCollectors modelsA model of a solar thermal collector mainly consists of the three following items:
Ratings data describing the parameters of individual collectors are available in Buildings.Fluid.SolarCollectors.Data. All ratings data was taken from the Solar Rating and Certification Corporation (SRCC) website. Data for concentrating, flat plate and tubular collectors are currently presented in separate data packages to improve ease of use. The name of any given collector data package begins with a code stating what type of collector it is. The codes are as follows:
Currently there are no concentrating models on the
SRCC website that provide all
of the data necessary for accurate use in the models available in
Buildings.Fluid.SolarCollectors. Namely, they lack data for
dp_nominal, dT_nominal and G_nominal.
This data must be obtained from other sources.
There are two test methods for solar thermal collectors. The American standard is ASHRAE93 and the European standard is EN12975. Models calculating solar gain and heat loss using coefficients from both test methods are available in Buildings.Fluid.SolarCollectors.BaseClasses. Users should be careful to ensure that the solar gain and heat loss models used in their simulation match the ratings data entered into the data package.
Finally, the parameters of the system must be defined. Most of the parameters are self-explanatory. The complex parameters are used as follows:
nSeg: This parameter refers to the number of segments between
the inlet and outlet of the system, not the number of segments in each solar
thermal collector.nColType: This parameter allows the user to specify how the
number of collectors in the system is defined. Options are Number,
allowing the user to enter a number of panels, or TotalArea,
allowing the user to enter a system area.
Number: If Number is selected for nColType
the user enters a number of panels. The simulation then identifies the area of the
system and uses that in solar gain and heat loss computations.TotalArea: If TotalArea is selected for
nColType the user enters a desired surface area of panels.
The model then uses this specified area in solar gain and heat loss
computations. The number of panels in the system is identified by dividing the
specified area by the area of each panel.SysConfig: This parameter allows the user to specify the installation
configuration of the system. Options are Series and Parallel.
The handling of dp_nominal is changed depending on the selection.
Series: If Series is selected it is assumed that
all panels in the system are connected in series. As a result there is a pressure
drop corresponding to dp_nominal for each panel and the effective
dp_nominal for the system is dp_nominal *
nPanels.Parallel: If Parallel is selected it is assumed
that all panels in the system are connected in parallel. As a result the fluid
flows through only a single panel and the dp_nominal for the system
is dp_nominal specified in the collector data package if the collector
field has a mass flow rate equal to per.m_flow_nominal.