It is a small software which is developed by MATLAB for modeling the energy system of a building or a HVAC system.
Method of Solution
In this code, the temperatures are considered variables of the problem, which are solved implicitly by solving a system of linear equations based on energy equations of each element.
Elements Classes
Boiler
The boiler contains an inlet fluid pipe, an outlet fluid pipe, a fluid tank which is heated up, and the rest. The class of boiler receives input values including the id of the inlet, the id of outlet, the solver, the specific heat capacity of the rest, the mass of the rest, specific heat capacity of the fluid, mass of the fluid, the boiler power, the mass flow rate, and the status. The inlet and outlet should be outlet and inlet of pipes which are connected to the boiler respectively. The solver is the class of the solver that is used. Next, there are specific heat capacity and mass of the boiler except containing fluid. Then, there are those of the fluid. The next argument is the power of the boiler. The mass flow rate also should be given as an input value. The status works as a switch in the boiler which can be controlled by the smart controller in the next stages of the project.
Specific Heat Capacity of the Boiler (without fluid)
double
J/(K.kg)
mass
Mass of the Boiler (without fluid)
double
kg
specific_heat_capacity_fluid
Specific Heat Capacity of the Fluid
double
J/(K.kg)
mass_fluid
Mass of Fluid inside the Boiler
double
kg
power
Power of the Boiler
double
W
mass_flow_rate
Mass Flow Rate of the Boiler
double
kg/s
status
Status of the Boiler (ON/OFF)
boolean
-
Create Matrix
create(solver)
Input
Description
Type
Unit
solver
Class of the Solver
solver
-
Pipe
Another element in the model is the pipe. The input values of the pipe class are the id of inlet, the id of outlet, the id of zone, the solver, specific heat capacity of the pipe wall, density of the pipe wall, specific heat capacity of the fluid, density of the fluid, mass flow rate of the fluid, inner heat transfer coefficient, outer heat transfer coefficient, thermal conductivity of the tube wall, inner radius of the pipe, outer radius of the pipe, and length of the pipe. The inlet and outlet of the pipe are the elements which are connected to the pipe. The zone which is in contact with the outer side of the pipe is also the argument of the class.
Specific Heat Capacity of the Pipe (without fluid)
double
J/(K.kg)
density
Density of the Pipe (without fluid)
double
kg/m3
specific_heat_capacity_fluid
Specific Heat Capacity of the Fluid
double
J/(K.kg)
density_fluid
Density of Fluid inside the Pipe
double
kg/m3
mass_flow_rate
Mass Flow Rate of the Pipe
double
kg/s
thermal_conductivity
Thermal Conductivity of the Pipe
double
W.m-1.K-1
thermal_conductivity_fluid
Thermal Conductivity of the Fluid
double
W.m-1.K-1
radius_inner
Inner Radius of the Pipe
double
m
radius_outer
Outer Radius of the Pipe
double
m
length
Length of the Pipe
double
m
dynamic_viscosity_fluid
Dynamic Viscosity of the Fluid
double
N·s/m2
dynamic_viscosity_air
Dynamic Viscosity of the Air
double
N·s/m2
density_air
Density of the Air
double
kg/m3
specific_heat_capacity_air
Specific Heat Capacity of the Air
double
J/(K.kg)
thermal_conductivity_air
Thermal Conductivity of the Air
double
W.m-1.K-1
Create Matrix
create(solver)
Input
Description
Type
Unit
solver
Class of the Solver
solver
-
Radiator
The input values of the radiator class are the id of inlet, the id of outlet, the id of zone, the solver, specific heat capacity of the radiator except containing fluid, mass of the radiator except containing fluid, specific heat capacity of the fluid, mass of fluid, mass flow rate of the fluid, heat transfer coefficient of the radiator to the zone, the surface of the radiator which is in contact to the air of the zone.
Specific Heat Capacity of the Radiator (without fluid)
double
J/(K.kg)
mass
Mass of the Radiator (without fluid)
double
kg
specific_heat_capacity_fluid
Specific Heat Capacity of the Fluid
double
J/(K.kg)
mass_fluid
Mass of Fluid inside the Radiator
double
kg
mass_flow_rate
Mass Flow Rate of the Radiator
double
kg/s
heat_transfer_coefficient
Heat Transfer Coefficient of the Radiator
double
W/(m2K)
surface
Surface of the Radiator
double
m2
Create Matrix
create(solver)
Input
Description
Type
Unit
solver
Class of the Solver
solver
-
Mixer
The mixer is an element that works as a mixer or manifold. It can mix multiple flowing fluids to multiple outlets. For the input arguments of the related class, there are the ids of inlets, the ids outlets, the solver, specific heat capacities of the inlets, mass flow rates of the inlets, and the fractions of outlets.
The zone class contains arguments including the id of the zone, the ids of neighbor zones as an array, the ids of radiators inlets as an array, the ids radiators outlets as an array, the solver, thickness of walls as an array, surface of the walls as an array, thickness of the windows as an array, surface of the windows as an array, surface of radiators as an array, heat transfer coefficient radiators as an array, density of the air, volume of the air, specific heat capacity of the air, density of the wall, volume of the wall, specific heat capacity of the wall, mass of the equipment, specific heat capacity of the equipment, thermal conductivity of the wall, thermal conductivity of the window.
The class of heat exchanger contains the id of supply inlet, the id of supply outlet, the id of demand inlet, the id of demand outlet, the solver, specific heat capacity of the supply, specific heat capacity of the demand, mass flow rate of the supply, mass flow rate of the demand, heat transfer coefficient of the heat exchanger, and contact surface of the heat exchanger as inputs.
The chiller class needs the following arguments as input: the id of condenser inlet, the id of condenser outlet, the id evaporator inlet, the id of evaporator outlet, the solver, specific heat capacity of the fluid, the cooling power, the coefficient of performance, mass flow rate of the condenser, mass flow rate of the evaporator, and the status of chiller.
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