Thermal Objects

This section presents an in-depth description of all objects available in SAInt to develop a thermal network model. Figure 1 shows the hierarchy and the parent-child relationships between base objects. Table 1 gives a quick and short description of the base objects. The thermal network consists of two symmetrical sides, known as the hot side and the cold side. For example for a district heating network the hot side (or supply side) delivers heat from the source to the users, while the cold side (or return side) brings the working fluid back to the source. The pipes on both sides have the same characteristics and make a closed loop, resulting in the mass flow rate to be constant between both sides. Only one side is displayed in the SAInt GUI.

For example, the top-level base object in a thermal network model is the "Thermal Network" object TNET. A thermal network contains many other different base objects, such as, heat demands HDEM, cold supply CSUP, or thermal lines TPI. A thermal branch TBR is the parent, and an thermal pipeline TPI is a child. A thermal network object has no parents but only children. A thermal line object TPI cannot be a parent, but only a child. See the schematic below for a visual representation of the complete hierarchical object structure for an thermal network model in SAInt.

Relationship between objects in thermal network. A child object is indicated by the head of a pointed arrow, while a parent is by the tail. Please, open the image in another window of your Internet browser to enlarge it.
Figure 1. Relationship between objects in thermal network. A child object is indicated by the head of a pointed arrow, while a parent is by the tail. Please, open the image in another window of your Internet browser to enlarge it.
Table 1. Icons and descriptions of object types in thermal network model.
Icon ObjType Display Name Description

tnet

TNET

Thermal Network

Models the characteristics and interactions of facilities and/or components of a thermal network. Serves as a container for all objects in the thermal network

tsub

TSUB

Thermal Sub

Models a subset of nodes, branches, and thermal externals of an thermal network. A thermal sub is branch-oriented, i.e., only thermal branches can be assigned to a thermal sub, and every thermal branch belongs to only one thermal sub

tzn

TZN

Thermal Zone

Models a subset of nodes, branches, and externals of a thermal network. A thermal zone is node-oriented, i.e., only thermal nodes can be assigned to a thermal zone, and every thermal node belongs to only one thermal zone

tgrp

TGRP

Thermal Group

Models a subset of different objects in a thermal network. Except for the thermal network, subs, and zones, any thermal object can be added to a thermal group. In contrast to thermal subs and zones, thermal groups do not follow any specific assignment rules. Thus, a thermal object can be part of multiple thermal groups

tno

TNO

Thermal Node

Models a physical or virtual location in the thermal network where heat (or cold) can be injected or extracted through externals (thermal demand, supply, storage, etc.)

tpi

TPI

Thermal Pipe

Models the transport of heat (or cold) between two distant locations

hsup

HSUP

Heat Supply

Models the injection of heat at a node

hdem

HDEM

Heat Demand

Models the consumption of heat at a node

1. Thermal network (TNET)

A thermal network object is the top parent object in any model of a thermal system in SAInt (Figure 1). A thermal network object is modeled as a directed graph consisting of a set of thermal nodes, branches, and externals that are connected with one another. A thermal network contains a description of all geometric, topological, and relational information, as well as all network child objects and their static and default properties that do not change during the execution of a simulation (e.g., the length and the diameter of a thermal pipe).

The nodes of a thermal network are objects describing a junction among two or more thermal branches and a physical or virtual location in the thermal network where thermal energy (heating or cooling) can be injected or extracted through externals (e.g., demand, supply, etc.).

The branches of a thermal network are objects that establish how nodes and externals are connected and affect the working fluid’s state as it flows through them. These branches are passive objects, such as thermal pipes, that do not inject or extract energy from the system. Branches of a thermal network are thermal pipes.

The externals of a thermal network represent objects injecting or extracting thermal energy (heating or cooling) from the system. Externals of a thermal network are supplies, demands, and storages.

Scenario events define a change in the settings of a thermal network object during the execution of a scenario. Thermal network events can be used to customize the network and simulation settings and to compare the effect of different assumptions across simulation scenarios. The following list describes the scenario events available for a network object.

  • Intro

  • derived-result

  • event-default

  • event-value

  • net-input

  • net-read-only

  • event

Summaries for the properties and the events of TNET.

Summary for the derived-result properties of TNET.
Extension Description UnitType

PMAX

Maximum value of the pressures of two sides of the nodes

P

TMAX

Maximum value of the temperatures of two sides of the nodes

T

PMIN

Minimum value of the pressures of two sides of the nodes

P

TMIN

Minimum value of the temperatures of two sides of the nodes

T

LOSSC

Total rate of heat transferred from the cold sides of the pipes to the ambient

TQ

FL

Total pressure loss due to friction in the two sides of the pipes

PD

PHI

Total net rate of heat transferred into externals (PHIIN - PHIOUT)

TQ

PHICOMP

Total rate of heat transferred into the heat supply to compensate the heat loss of the pipes and the mismatch between the supplies and the demands

TQ

LOSS

Total rate of heat transferred from the hot sides of the pipes to the ambient

TQ

PHIIN

Total rate of heat transferred into the externals

TQ

PHIOUT

Total rate of heat transferred out of the externals

TQ

Summary for the event-default properties of TNET.
Extension Description UnitType

TAMBDEF

Default ambient temperature. The "TAMB" event of TNET, TSUB, or TPI can override it

T

Summary for the event-value properties of TNET.
Extension Description UnitType

TAMB

Ambient temperature. The "TAMB" event of TSUB or TPI can override it

T

Summary for the net-input properties of TNET.
Extension Description UnitType

PAMB

Ambient pressure

PD

CRSType

Network coordinate reference system for the node locations

Info

Information related to the network model. Any character, including non-alphanumeric, is allowed

PDMIN

Minimum pressure difference between two sides of all the nodes

PD

TimeModified

Time of last network model modification. Updated automatically when changes at network level are saved

Version

Network version. Any character, including non-alphanumeric, is allowed

Summary for the net-read-only properties of TNET.
Extension Description UnitType

Name

Name of the network model. Permitted characters are letters, numbers, and underscore ("_"). The name should start with a letter, and have a length of 1 to 30 characters.

NetType

Network Type

NUMBR

Number of branches in the network, sub, zone or group

NO

NUMXT

Number of externals in the network, sub, zone or group

NO

NUMLOOP

Number of closed loops in the network, sub, zone or group

NO

NUMNO

Number of nodes in the network, sub, zone or group

NO

ObjType

Object Type

UID

Unique identifier for the object which cannot be changed during the lifetime of the object

ImageDirectory

Directory path to image file

ModelDir

Directory Path to Model file

Summary for the events of TNET.
Parameter Type Description UnitType

TAMB

Ambient

Ambient temperature. Minimum: 183.15. Maximum: 333.15.

T

2. Thermal network container

The child objects of a network can be grouped into the following subsets, also referred to as "containers": sub, zone, and group. These arrangements can be used to define relevant information for a network, or they can simply be used to conveniently aggregate outputs of a scenario.

2.1. Thermal sub (TSUB)

A sub (also referred to as sub-network or sub-system) is a subset of nodes, branches, and externals of a network. A sub is branch-oriented, i.e., only branches can be assigned to a sub, and every branch belongs to only one sub. The FromNode and ToNode of a branch, as well as the externals connected to these two nodes, are implicitly added to the sub. Thus, nodes connecting branches of different subs and the externals connected to these nodes are always included in multiple subs. But all properties of a sub are determined by the branches belonging to it.

  • Intro

  • derived-result

  • event-value

  • net-input

  • net-read-only

  • event

Summaries for the properties and the events of TSUB.

Summary for the derived-result properties of TSUB.
Extension Description UnitType

PMAX

Maximum value of the pressures of two sides of the nodes

P

TMAX

Maximum value of the temperatures of two sides of the nodes

T

PMIN

Minimum value of the pressures of two sides of the nodes

P

TMIN

Minimum value of the temperatures of two sides of the nodes

T

LOSSC

Total rate of heat transferred from the cold sides of the pipes to the ambient

TQ

FL

Total pressure loss due to friction in the two sides of the pipes

PD

PHI

Total net rate of heat transferred into externals (PHIIN - PHIOUT)

TQ

PHICOMP

Total rate of heat transferred into the heat supply to compensate the heat loss of the pipes and the mismatch between the supplies and the demands

TQ

LOSS

Total rate of heat transferred from the hot sides of the pipes to the ambient

TQ

PHIIN

Total rate of heat transferred into the externals

TQ

PHIOUT

Total rate of heat transferred out of the externals

TQ

Summary for the event-value properties of TSUB.
Extension Description UnitType

TAMB

Ambient temperature. It can override "TNET.TAMB" but can be overridden by "TPI.TAMB"

T

Summary for the net-input properties of TSUB.
Extension Description UnitType

Info

Information entered for the object. Any character, including non-alphanumeric, is allowed

Name

Object Name. Permitted characters are letters, numbers, and underscore ("_"). The name should start with a letter, and have a length of 1 to 30 characters. The name should be unique for each object type

Summary for the net-read-only properties of TSUB.
Extension Description UnitType

NetType

Network Type

NUMBR

Number of branches in the network, sub, zone or group

NO

NUMXT

Number of externals in the network, sub, zone or group

NO

NUMLOOP

Number of closed loops in the network, sub, zone or group

NO

NUMNO

Number of nodes in the network, sub, zone or group

NO

ObjType

Object Type

UID

Unique identifier for the object which cannot be changed during the lifetime of the object

Summary for the events of TSUB.
Parameter Type Description UnitType

TAMB

Ambient

Ambient temperature. Minimum: 183.15. Maximum: 333.15.

T

2.2. Thermal zone (TZN)

A subset of nodes, branches, and externals of a thermal network. Differently from subs, zones are node-oriented, i.e., only nodes can be assigned to a zone, and every node belongs to one zone. Branches with a FromNode and ToNode belonging to the same zone are implicitly added to the corresponding zone. In contrast, branches with a FromNode and ToNode belonging to two different zones do not belong to any zone. Externals are also implicitly added to the zone of the node they are connected to. But all properties of a zone are determined by the nodes belonging to it.

  • Intro

  • derived-result

  • net-input

  • net-read-only

Summaries for the properties and the events of TZN.

Summary for the derived-result properties of TZN.
Extension Description UnitType

PMAX

Maximum value of the pressures of two sides of the nodes

P

TMAX

Maximum value of the temperatures of two sides of the nodes

T

PMIN

Minimum value of the pressures of two sides of the nodes

P

TMIN

Minimum value of the temperatures of two sides of the nodes

T

LOSSC

Total rate of heat transferred from the cold sides of the pipes to the ambient

TQ

FL

Total pressure loss due to friction in the two sides of the pipes

PD

PHI

Total net rate of heat transferred into externals (PHIIN - PHIOUT)

TQ

PHICOMP

Total rate of heat transferred into the heat supply to compensate the heat loss of the pipes and the mismatch between the supplies and the demands

TQ

LOSS

Total rate of heat transferred from the hot sides of the pipes to the ambient

TQ

PHIIN

Total rate of heat transferred into the externals

TQ

PHIOUT

Total rate of heat transferred out of the externals

TQ

Summary for the net-input properties of TZN.
Extension Description UnitType

Info

Information entered for the object. Any character, including non-alphanumeric, is allowed

Name

Object Name. Permitted characters are letters, numbers, and underscore ("_"). The name should start with a letter, and have a length of 1 to 30 characters. The name should be unique for each object type

Summary for the net-read-only properties of TZN.
Extension Description UnitType

NetType

Network Type

NUMBR

Number of branches in the network, sub, zone or group

NO

NUMXT

Number of externals in the network, sub, zone or group

NO

NUMLOOP

Number of closed loops in the network, sub, zone or group

NO

NUMNO

Number of nodes in the network, sub, zone or group

NO

ObjType

Object Type

UID

Unique identifier for the object which cannot be changed during the lifetime of the object

2.3. Thermal group (TGRP)

A group is a subset of different child object types (e.g., nodes, branches, externals, etc.) of the whole network. In contrast to subs and zones, groups do not follow any specific assignment rules. Thus, a child object can be assigned to multiple groups, and a group can have as many child objects assigned to it as there are child objects in the network.

  • Intro

  • derived-result

  • net-input

  • net-read-only

Summaries for the properties and the events of TGRP.

Summary for the derived-result properties of TGRP.
Extension Description UnitType

PMAX

Maximum value of the pressures of two sides of the nodes

P

TMAX

Maximum value of the temperatures of two sides of the nodes

T

PMIN

Minimum value of the pressures of two sides of the nodes

P

TMIN

Minimum value of the temperatures of two sides of the nodes

T

LOSSC

Total rate of heat transferred from the cold sides of the pipes to the ambient

TQ

FL

Total pressure loss due to friction in the two sides of the pipes

PD

PHI

Total net rate of heat transferred into externals (PHIIN - PHIOUT)

TQ

PHICOMP

Total rate of heat transferred into the heat supply to compensate the heat loss of the pipes and the mismatch between the supplies and the demands

TQ

LOSS

Total rate of heat transferred from the hot sides of the pipes to the ambient

TQ

PHIIN

Total rate of heat transferred into the externals

TQ

PHIOUT

Total rate of heat transferred out of the externals

TQ

Summary for the net-input properties of TGRP.
Extension Description UnitType

Info

Information entered for the object. Any character, including non-alphanumeric, is allowed

Name

Object Name. Permitted characters are letters, numbers, and underscore ("_"). The name should start with a letter, and have a length of 1 to 30 characters. The name should be unique for each object type

Summary for the net-read-only properties of TGRP.
Extension Description UnitType

NetType

Network Type

NUMCNSTR

Number of branches in the network, sub, zone or group

NO

NUMBR

Number of branches in the network, sub, zone or group

NO

NUMXT

Number of externals in the network, sub, zone or group

NO

NUMLOOP

Number of closed loops in the network, sub, zone or group

NO

NUMNO

Number of nodes in the network, sub, zone or group

NO

ObjType

Object Type

UID

Unique identifier for the object which cannot be changed during the lifetime of the object

3. Thermal node (TNO)

Nodes represent objects describing a junction among two or more thermal branches, as well as a location in the thermal network where thermal energy can be injected or extracted through externals (e.g., heat demand, cold supply, etc.).

  • Intro

  • base-result

  • derived-result

  • event-default

  • event-value

  • net-input

  • net-read-only

  • event

Summaries for the properties and the events of TNO.

Summary for the base-result properties of TNO.
Extension Description UnitType

PC

Pressure of the cold side

P

TC

Temperature of the flows out of the cold side

T

PH

Pressure of the hot side

P

TH

Temperature of the flows out of the hot side

T

State

Current operating state of object. Permitted states are ON and OFF. When referred to a node, all externals connected to the node inherit the state

Summary for the derived-result properties of TNO.
Extension Description UnitType

PHI

Total net rate of heat transferred into externals (PHIIN - PHIOUT)

TQ

PHIIN

Total rate of heat transferred into externals

TQ

Q

Total flow from the cold side to the hot side via externals

MDOT

PHIOUT

Total rate of heat transferred out of externals

TQ

PD

Pressure difference between the hot side and the cold side ("PH" - "PC")

PD

Summary for the event-default properties of TNO.
Extension Description UnitType

PMAXDEF

Default maximum pressure of the hot side and the cold side

P

PMINDEF

Default minimum pressure of the hot side and the cold side

P

Summary for the event-value properties of TNO.
Extension Description UnitType

PMAX

Maximum pressure of the hot side and the cold side

P

PMIN

Minimum pressure of the hot side and the cold side

P

PSET

Pressure set-point for the hot side. There should only be one such event in each isolated network

P

Summary for the net-input properties of TNO.
Extension Description UnitType

Alias

Alternative object name. Any character, including non-alphanumeric, is allowed

H

Elevation

H

Info

Information entered for the object. Any character, including non-alphanumeric, is allowed

InService

Indicates if an object is considered or disregarded in the execution of a scenario. Externals connected to the node inherit the "inService" status of the node

Name

Object Name. Permitted characters are letters, numbers, and underscore ("_"). The name should start with a letter, and have a length of 1 to 30 characters. The name should be unique for each object type

Visible

If true, the object symbol will be visible in maps

NO

X

Cartesian X coordinate for visualizing the node in the map. Externals assigned to the node are not displayed

XY

Y

Cartesian Y coordinate for visualizing the node in the map. Externals assigned to the node are not displayed

XY

ZoneName

ZoneName of the zone the node belongs to

Summary for the net-read-only properties of TNO.
Extension Description UnitType

NetType

Network Type

ID

Object Identification

ObjType

Object Type

UID

Unique identifier for the object which cannot be changed during the lifetime of the object

Degree

Number of connected branches and externals

Summary for the events of TNO.
Parameter Type Description UnitType

PMAX

Constraint

Maximum pressure of both sides. Minimum: 0.0.

P

PMIN

Constraint

Minimum pressure of both sides. Minimum: 0.0.

P

PSET

ControlSetPoint

Pressure of the hot side. Minimum: 0.0.

P

The injection/extraction of water is not considered for now.

4. Thermal branch (TBR)

A branch is a general type of object which describes a generic connection between two nodes in the network. Different types of branches exist in SAInt and the following sections provides more details on each of them.

4.1. Thermal pipe (TPI)

The thermal pipe transports thermal energy via a working fluid from one place to another. A pipe object represents both the pipe on the hot side and the corresponding pipe on the cold side. The direction of such two pipes are the same. The following two images mainly illustrate the branch direction, the flow directions, and temperatures of a thermal pipe.

tpi directions
Figure 2. Illustration of a thermal network with one supply, one pipe and one demand.
tpi directions inv
Figure 3. Illustration of the thermal network with one supply, one pipe and one demand. The branch direction of the pipe is reversed.
The parameters and events of the pipe on the cold side are the same as its counterpart on the hot side.
  • Intro

  • base-result

  • derived-result

  • event-value

  • net-input

  • net-read-only

  • event

Summaries for the properties and the events of TPI.

Summary for the base-result properties of TPI.
Extension Description UnitType

TDC

Downstream temperature of the cold side

T

TDH

Downstream temperature of the hot side

T

State

Current operating state of object. Permitted states are ON and OFF. When referred to a node, all externals connected to the node inherit the state

Q

Mass flow rate of the hot side

MDOT

Summary for the derived-result properties of TPI.
Extension Description UnitType

PIC

Pressure of the cold side ("PC") of the "from" node

P

TIC

Temperature of the code side ("TC") of the "from" node

T

LOSSC

Heat transferred from the cold side to the ambient

TQ

POC

Pressure of the cold side ("PC") of the "to" node

P

TOC

Temperature of the cold side ("TC") of the "to" node

T

PDC

Pressure difference between the nodes of the cold side in the branch direction ("PIC" - "POC")

PD

TDROPC

Temperature drop on the cold side of the pipe in the flow direction

TD

TUC

Upstream temperature of the cold side based on the flow direction

T

V

Flow velocity of the hot side

VEL

FL

Pressure loss due to friction in the two sides

PD

PI

Pressure of the hot side ("PH") of the "from" node

P

TIH

Temperature of the hot side ("TH") of the "from" node

T

LOSS

Heat transferred from the hot side to the ambient

TQ

PO

Pressure of the hot side ("PH") of the "to" node

P

TOH

Temperature of the hot side ("TH") of the "to" node

T

PD

Pressure difference between the nodes of the hot side in the branch direction ("PI" - "PO")

PD

TDROPH

Temperature drop on the hot side of the pipe in the flow direction

TD

TUH

Upstream temperature of the hot side based on the flow direction

T

QVOL

Volumetric flow rate of the hot side

QVOL

Summary for the event-value properties of TPI.
Extension Description UnitType

TAMB

Ambient temperature. It can override "TAMB" of TNET and "TSUB"

T

Summary for the net-input properties of TPI.
Extension Description UnitType

Alias

Alternative object name. Any character, including non-alphanumeric, is allowed

DrawLine

If true, element will be drawn as a straight line and internal points will be neglected

NO

FromName

Name of FromNode

Info

Information entered for the object. Any character, including non-alphanumeric, is allowed

D

Inner pipe diameter or design diameter of non-pipe branches

D

RO

Inner wall roughness of pipeline

RO

InService

Indicates if an object is considered or disregarded in the execution of a scenario. Externals connected to the node inherit the "inService" status of the node

HTCLIN

Linear heat transfer coefficient

HTCLIN

Name

Object Name. Permitted characters are letters, numbers, and underscore ("_"). The name should start with a letter, and have a length of 1 to 30 characters. The name should be unique for each object type

Eff

Pipeline efficiency

ND

L

Pipeline length

L

SubName

Sub the branch belongs to

ToName

Name of ToNode

Visible

If true, the object symbol will be visible in maps

NO

Summary for the net-read-only properties of TPI.
Extension Description UnitType

A

Cross sectional area

AREA

LGEO

Length According to Map Coordinates

L

ALPHA

Pipeline inclination

ANGLE

LD

Difference between actual pipeline length and geographic length

L

NetType

Network Type

ID

Object Identification

ObjType

Object Type

UID

Unique identifier for the object which cannot be changed during the lifetime of the object

Summary for the events of TPI.
Parameter Type Description UnitType

TAMB

Ambient

Ambient temperature. Minimum: 183.15. Maximum: 333.15.

T

5. Thermal external (TXT)

A thermal external represents a device or a system that interacts with a thermal node by either consuming or producing thermal energy. It can represent different elements of a thermal network, such as a heat pump, combined power and heat facility, absorption chiller, heat sink, or thermal storage. A thermal external has a single connection to a thermal node, and multiple thermal externals can connect to the same thermal node.

Multiple externals at the same node can connect two sides of a node in parallel, which is illustrated below. Note the details outside the district heating network (indicated by the gray boxes) are not modeled in SAInt. For example, the temperature-related properties, HSUP.PLANT.Q, and HSUP.PLANT.PHI model the left side of the heat exchanger of HSUP.PLANT.

parallel text
Figure 4. Illustration of a HDEM and a HSUP connecting two sides of the same TNO in parallel.

5.1. Heat demand (HDEM)

A heat demand represents a heat exchanger which connects the hot side of the node to the cold side. The heat demand acts as a heat sink extracting thermal energy from the network for a specific purpose (e.g., household, commercial, industrial, etc.).

  • Intro

  • base-result

  • derived-result

  • event-default

  • event-value

  • net-input

  • net-read-only

  • event

Summaries for the properties and the events of HDEM.

Summary for the base-result properties of HDEM.
Extension Description UnitType

CTRL

Control mode, which is determined by the events and affects which events are considered

NO

TD

Downstream temperature

T

Q

Mass flow rate from the hot side to the cold side

MDOT

State

Current operating state of object. Permitted states are ON and OFF. When referred to a node, all externals connected to the node inherit the state

PHI

Heat exchanged out of the flow

TQ

Summary for the derived-result properties of HDEM.
Extension Description UnitType

TI

Temperature of the flows out of the hot side

T

TO

Temperature of the flows out of the cold side

T

TDROP

Temperature drop between the hot and the cold side in the flow direction

TD

TU

Upstream temperature, which is the temperature of the flows out of the hot side

T

Summary for the event-default properties of HDEM.
Extension Description UnitType

QMAXDEF

Default maximum mass flow rate from the hot side to the cold side

MDOT

PHIMAXDEF

Default maximum amount of heat exchanged out of the flow

TQ

TMAXDEF

Default maximum value of the downstream temperature and the upstream temperature

T

TMINDEF

Default minimum value of the downstream temperature and the upstream temperature

T

Summary for the event-value properties of HDEM.
Extension Description UnitType

TDSET

Set-point of the downstream temperature

T

QSET

Set-point of the mass flow rate from the hot side to the cold side

MDOT

PHISET

Set-point of exchanged heat

TQ

QMAX

Maximum mass flow rate from the hot side to the cold side

MDOT

PHIMAX

Maximum amount of heat exchanged out of the flow

TQ

TMAX

Maximum value of the downstream temperature and the upstream temperature

T

TMIN

Minimum value of the downstream temperature and the upstream temperature

T

Summary for the net-input properties of HDEM.
Extension Description UnitType

Alias

Alternative object name. Any character, including non-alphanumeric, is allowed

Info

Information entered for the object. Any character, including non-alphanumeric, is allowed

InService

Indicates if an object is considered or disregarded in the execution of a scenario. Externals connected to the node inherit the "inService" status of the node

Name

Object Name. Permitted characters are letters, numbers, and underscore ("_"). The name should start with a letter, and have a length of 1 to 30 characters. The name should be unique for each object type

NodeName

Name of node the external is connected to

Visible

If true, the object symbol will be visible in maps

NO

Summary for the net-read-only properties of HDEM.
Extension Description UnitType

NetType

Network Type

ID

Object Identification

ObjType

Object Type

UID

Unique identifier for the object which cannot be changed during the lifetime of the object

Summary for the events of HDEM.
Parameter Type Description UnitType

PHIMAX

Constraint

Maximum heat out of the flow. Minimum: 0.0.

TQ

PHISET

ControlSetPoint

Heat out of the flow. Minimum: 0.0.

TQ

QMAX

Constraint

Maximum mass flow rate. Minimum: 0.0.

MDOT

QSET

ControlSetPoint

Mass flow rate. Minimum: 0.0.

MDOT

TDSET

ControlSetPoint

Downstream temperature. Minimum: 273.15.

T

TMAX

Constraint

Maximum temperature of both sides. Minimum: 183.15.

T

TMIN

Constraint

Minimum temperature of both sides. Minimum: 183.15.

T

There is no property for the default values of QMAX, TSET, or PHISET.

Three control modes and their combinations of events of the heat demand are summarized in the following table.

Table 2. Three control modes of the heat demand.
Short Name Description TDSET QSET PHISET Implemented

Heat

TDSET and PHISET are specified. Phi will equal PHISET.

Flow

TDSET and QSET are specified.

UndefTemp

PHISET and QSET are specified. Phi will equal PHISET. Not common.

The last control mode will be implemented in the future.

There are five invalid combinations of events, which are summarized in the following table. If any demand has one of these combinations, the simulation will not start.

Table 3. Five invalid combinations of events for the heat demand and the reasons.
Short Name TDSET QSET PHISET Reason

Undef

under-determined

MissFlow

under-determined

MissTempHeat

under-determined

MissTempFlow

under-determined

ExtraFlow

overdetermined

5.2. Heat supply (HSUP)

A heat supply transports flow from the cold side of the node to the hot side. Some heat is exchanged into the flow.

A heat supply represents a heat exchanger which connects the hot side of the node to the cold side. The heat supply acts as a heat source injecting thermal energy to the network from a heat production facility or unit (e.g., combined heat and power (CHP), heat pump, boiler, etc.).

  • Intro

  • base-result

  • derived-result

  • event-default

  • event-value

  • net-input

  • net-read-only

  • event

Summaries for the properties and the events of HSUP.

Summary for the base-result properties of HSUP.
Extension Description UnitType

CTRL

Control mode, which is determined by the events and affects which events are considered

NO

TD

Downstream temperature

T

PHI

Heat exchanged into the flow

TQ

Q

Mass flow rate from the cold side to the hot side

MDOT

State

Current operating state of object. Permitted states are ON and OFF. When referred to a node, all externals connected to the node inherit the state

Summary for the derived-result properties of HSUP.
Extension Description UnitType

TI

Temperature of the flows out of the cold side

T

TO

Temperature of the flows out of the hot side

T

TDROP

Temperature drop between the hot and the cold side in the flow direction

TD

TU

Upstream temperature, which is the temperature of the flows out of the cold side

T

Summary for the event-default properties of HSUP.
Extension Description UnitType

QMAXDEF

Default maximum mass flow rate from the cold side to the hot side

MDOT

PHIMAXDEF

Default maximum amount of heat exchanged into the flow

TQ

TMAXDEF

Default maximum value of the downstream temperature and the upstream temperature

T

TMINDEF

Default minimum value of the downstream temperature and the upstream temperature

T

Summary for the event-value properties of HSUP.
Extension Description UnitType

PFSET

Absolute participating factor. A positive value means the supply participates in the distributed compensation. Will be scaled down to the relative participating factor based on the sum of all the absolute participating factors

ND

TDSET

Set-point of the downstream temperature

T

QSET

Set-point of the mass flow rate from the cold side to the hot side

MDOT

PHISET

Set-point of exchanged heat

TQ

QMAX

Maximum mass flow rate from the cold side to the hot side

MDOT

PHIMAX

Maximum amount of heat exchanged into the flow

TQ

TMAX

Maximum value of the downstream temperature and the upstream temperature

T

TMIN

Minimum value of the downstream temperature and the upstream temperature

T

Summary for the net-input properties of HSUP.
Extension Description UnitType

Alias

Alternative object name. Any character, including non-alphanumeric, is allowed

Info

Information entered for the object. Any character, including non-alphanumeric, is allowed

InService

Indicates if an object is considered or disregarded in the execution of a scenario. Externals connected to the node inherit the "inService" status of the node

Name

Object Name. Permitted characters are letters, numbers, and underscore ("_"). The name should start with a letter, and have a length of 1 to 30 characters. The name should be unique for each object type

NodeName

Name of node the external is connected to

Visible

If true, the object symbol will be visible in maps

NO

Summary for the net-read-only properties of HSUP.
Extension Description UnitType

NetType

Network Type

ID

Object Identification

ObjType

Object Type

UID

Unique identifier for the object which cannot be changed during the lifetime of the object

Summary for the events of HSUP.
Parameter Type Description UnitType

PFSET

ControlSetPoint

Absolute participating factor. Minimum: 0.0.

ND

PHIMAX

Constraint

Maximum heat into the flow. Minimum: 0.0.

TQ

PHISET

ControlSetPoint

Heat into the flow. Minimum: 0.0.

TQ

QMAX

Constraint

Maximum mass flow rate. Minimum: 0.0.

MDOT

QSET

ControlSetPoint

Mass flow rate. Minimum: 0.0.

MDOT

TDSET

ControlSetPoint

Downstream temperature. Minimum: 273.15.

T

TMAX

Constraint

Maximum temperature of both sides. Minimum: 183.15.

T

TMIN

Constraint

Minimum temperature of both sides. Minimum: 183.15.

T

There is no property for the default values of TSET, PFSET, and PHISET.

Five control modes and their combinations of events of the heat supply are summarized in the following table.

Table 4. Five control modes of the heat supply.
Short Name Description TDSET PHISET QSET PFSET Implemented

Heat

TDSET and PHISET are specified. PHI will equal PHISET.

=0 or ✗

Flow

TDSET and QSET are specified.

CompHeat

Participate in distributed compensation with unknown Q. PHISET is zero by default, so TDSET, PHISET, and PFSET are specified.

✓ or ✗

>0

UndefTemp

QSET and PHISET are specified. Not common.

CompUndefTemp

Participate in distributed compensation with unknown TD. PHISET is 0 by default, so QSET, PHISET and PFSET are specified. Not common.

✓ or ✗

>0

The last two control modes will be implemented in the future.
At least one heat supply must has non-zero PFSET. Multiple heat supplies with PFSET mean they participate in the distributed compensation together.

There are seven invalid combinations of events, which are summarized in the following table. If any supply has one of these combinations, the simulation will not start.

Table 5. Seven incorrect ways to control the heat supply and the reasons.
Short Name TDSET QSET PHISET PFSET Reason

Undef

under-determined

Miss

under-determined

MissTempFlow

under-determined

MissTempHeat

under-determined

MissingTempCompHeat

✓ or ✗

under-determined

ExtraFlow

overdetermined

ExtraFlowComp

✓ or ✗

overdetermined