#### 7.1.3.5 IfcAirToAirHeatRecovery

| Echangeur air-air
| Wärmerückgewinner

An air-to-air heat recovery device employs a counter-flow heat exchanger between inbound and outbound air flow. It is typically used to transfer heat from warmer air in one chamber to cooler air in the second chamber (i.e., typically used to recover heat from the conditioned air being exhausted and the outside air being supplied to a building), resulting in energy savings from reduced heating (or cooling) requirements.

> HISTORY New entity in IFC4

## Mechanical System Design

Instance diagram

Object Typing

The Object Typing concept applies to this entity.

Exchange |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Import | - | R | R | - | - | R
Export | - | R | R | - | - | R

Assigned Group

The Assigned Group concept applies to this entity as shown in Table 6.

Type
IfcDistributionSystem
Table 6 — IfcAirToAirHeatRecovery Assigned Group

Exchange |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Import | - | R | R | - | - | R
Export | - | R | R | - | - | R

Classification

The Classification concept applies to this entity.

Exchange |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Import | - | R | R |  | - | R
Export | - | R | R |  | - | R

Identity

The Identity concept applies to this entity.

Exchange |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Import |  | R | R |  |  | R
Export |  | R | R |  |  | R

XSD Specification:

<xs:element name="IfcAirToAirHeatRecovery" type="ifc:IfcAirToAirHeatRecovery" substitutionGroup="ifc:IfcEnergyConversionDevice" nillable="true"/>
<xs:complexType name="IfcAirToAirHeatRecovery">
<xs:complexContent>
<xs:extension base="ifc:IfcEnergyConversionDevice"/>
</xs:complexContent>
</xs:complexType>

EXPRESS Specification:

ENTITY IfcAirToAirHeatRecovery

| SUBTYPE OF (IfcEnergyConversionDevice);

PredefinedType | : | OPTIONAL IfcStrippedOptional;

| WHERE

CorrectPredefinedType | : | NOT(EXISTS(PredefinedType)) OR (PredefinedType <> IfcAirToAirHeatRecoveryTypeEnum.USERDEFINED) OR ((PredefinedType = IfcAirToAirHeatRecoveryTypeEnum.USERDEFINED) AND EXISTS (SELF\IfcObject.ObjectType));
CorrectTypeAssigned | : | (SIZEOF(IsTypedBy) = 0) OR ('IFCHVACDOMAIN.IFCAIRTOAIRHEATRECOVERYTYPE' IN TYPEOF(SELF\IfcObject.IsTypedBy[1].RelatingType));

END_ENTITY;

Formal Propositions:

CorrectPredefinedType | : | Either the PredefinedType attribute is unset (e.g. because an IfcAirToAirHeatRecoveryType is associated), or the inherited attribute ObjectType shall be provided, if the PredefinedType is set to USERDEFINED.
CorrectTypeAssigned | : | Either there is no air-to-air heat recovery type object associated, i.e. the IsTypedBy inverse relationship is not provided, or the associated type object has to be of type IfcAirToAirHeatRecoveryType.

Inheritance Graph:

ENTITY IfcAirToAirHeatRecovery

| ENTITY IfcRoot

GlobalId | : | IfcGloballyUniqueId;
OwnerHistory | : | OPTIONAL IfcOwnerHistory;
Name | : | OPTIONAL IfcLabel;
Description | : | OPTIONAL IfcText;

| ENTITY IfcObjectDefinition

| INVERSE

HasAssignments | : | SET OF IfcRelAssigns FOR RelatedObjects;
HasContext | : | SET [0:1] OF IfcRelDeclares FOR RelatedDefinitions;
IsDecomposedBy | : | SET OF IfcRelAggregates FOR RelatingObject;
Decomposes | : | SET [0:1] OF IfcRelAggregates FOR RelatedObjects;
HasAssociations | : | SET OF IfcRelAssociates FOR RelatedObjects;

| ENTITY IfcObject

ObjectType | : | OPTIONAL IfcStrippedOptional;

| INVERSE

IsTypedBy | : | SET [0:1] OF IfcRelDefinesByType FOR RelatedObjects;

| ENTITY IfcProduct

ObjectPlacement | : | OPTIONAL IfcStrippedOptional;
Representation | : | OPTIONAL IfcStrippedOptional;

| INVERSE

| ENTITY IfcElement

Tag | : | OPTIONAL IfcStrippedOptional;

| INVERSE

| ENTITY IfcDistributionElement

| INVERSE

HasPorts | : | SET OF IfcRelConnectsPortToElement FOR RelatedElement;

| ENTITY IfcDistributionFlowElement

| INVERSE

| ENTITY IfcEnergyConversionDevice

| ENTITY IfcAirToAirHeatRecovery

PredefinedType | : | OPTIONAL IfcStrippedOptional;

END_ENTITY;

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