HVAC Auxiliaries Editor


 

 

Description


The “HVAC” tab defines various parameters for heating, ventilation and air conditioning (HVAC) auxiliaries used on the vehicle, calculated from the HVAC Steady State Model (HVAC SSM):

·         Disable HVAC Module [tickbox]

·         Filepath to the Steady State Model File (.AHSM)

Files can be imported by clicking the browse button adjacent to the HVAC “Steady State Model File (.AHSM)” text box.

·         Filepath to the Bus Parameter Database (.ABDB)

Files can be imported by clicking the browse button adjacent to the HVAC SSM bus parameters database file (.ABDB) text box.  The bus parameter database contains a list of default parameters for a number of pre-existing/defined buses that can be quickly switched between within the HVAC SSM Editor module.


Outputs from the HVAC SSM include:

·         Electrical Load Power Watts

·         Mechanical Load Power Watts

·         Fuelling Litres Per Hour



HVAC Steady-State Model Editor


The HVAC Steady-State Model (HVAC SSM) Editor defines various data and parameters for calculation of HVAC auxiliary demands (electrical, mechanical and fuelling) from the vehicle, replicating the key inputs/functionality from the HVAC CO2SIM model developed for ACEA:

·         Bus Parameters

·         Boundary Conditions

·         Other

·         Tech List Input

·         Diagnostics


At the top of the window, two sets of outputs are presented for electrical, mechanical and fuelling demand:

·         ‘Base’ values: These are the calculated resulting demands from the inputs on the ‘Bus Parameters’, ‘Boundary Conditions’ and ‘Other’ tabs.

·         ‘Adjusted’ values: these are the final values output from the model, which additionally factor in the HVAC technologies included in the ‘Tech List Input’ tab.


Bus Parameters


Input bus parameters can be edited directly or imported/calculated from the Bus Parameter Database (.abdb) file via the ‘<Select>’ drop-down box at the top of the page. Parameters in the accompanying database file (.abdb) include:

·         Bus Model Name (free text)

·         Registered passengers

·         Type (i.e. ‘raised floor’ = Class III, ‘semi low floor’ = Class II, or ‘low floor’ = Class I)

·         Is Double Decker [tick box]

·         Length in m,

·         Wide in m,

·         Height in m,

·         [Engine Type (only ‘diesel’ is currently supported), only when creating a ‘New’ entry]

·         Other fields, that are greyed out, are locked and not editable, containing fixed default values or calculations.

 


Boundary Conditions


On this tab the various boundary conditions for the HVAC SSM calculations can be set. Certain fields (greyed out) are locked and not editable, containing fixed default values or calculations.


Other


On this tab a number of other parameters for the HVAC SSM calculations can be set:

·         Environmental conditions: when in ‘Batch Mode’ a climatic conditions dataset (.aenv) file must be used containing a series of environmental conditions. Otherwise single values for temperature and solar load may be input (these fields are locked/not used when in batch mode).

·         AC System specifications/type: the AC-Compressor Type selection determines the COP value used, according to the specification of the project steering group.

·         Ventilation settings

·         Auxiliary Heater parameters: the power of the fuel fired heater may be included, other fields are provided for information only and are locked. The ‘Engine Waste Heat’ values are calculated during the actual model runs, which are determined via a pre-run of the model over the selected drive-cycle.


Tech List Input


To determine energy consumption of a certain bus-HVAC system combination, a customisable list of technologies may be added/edited on this tab to allow to take special features into account which have a reducing or increasing influence. Because several technologies are only available for certain bus types, the list has to be bus type-specific. The technologies list and the default values has been populated according to the steering group recommendations, however these may be deleted, edited or added to as required on this tab in Engineering mode.

Diagnostics

The final ‘Diagnostics’ tab provides a summary of the resulting outputs from the HVAC Tech List tab.



Default Values



The following table provides a summary of the default values that are populated whenever a new advanced auxiliaries (.AAUX) file is created from scratch.  The table also indicates the editable/default status of the relevant parameters in the VECTO UI in Engineering mode, and the recommended status in Declaration mode (not currently implemented).  The default values / parameter status has been agreed with the project steering group.

Default parameter values and editable status for the HVAC module

Category/Input

Default value

Editable Status by Mode

Engineering

Declaration

INP - BusParameters tab

 

 

 

Bus Parameterisation

 

 

 

Select

<Select>

 

 

Bus Model

<ABDB or input>

Open/editable

Locked default

Number of Passengers

<ABDB or input>

Open/editable

Locked default

Bus Type

<ABDB or input>

Open/editable

Locked default

Double Decker?

No

Open/editable

Open/OEM data

Bus Length (m)

<ABDB or input>

Open/editable

Locked default

Bus Width (m)

<ABDB or input>

Open/editable

Locked default

Bus Height (m)

<ABDB or input>

Open/editable

Locked Calc

Bus Floor Surface Area (m^2)

Calculation

Locked Calc

Locked Calc

Bus Window Surface (m^2)

Calculation

Locked Calc

Locked Calc

Bus Surface Area (m^2)

Calculation

Locked Calc

Locked Calc

Bus Volume (m^3)

Calculation

Locked Calc

Locked Calc

INP - BusParameters tab

 

 

 

Boundary Conditions:

 

 

 

G-Factor **

0.95

Open/editable

Open/editable

Solar Clouding

0.8

Locked Calc

Locked Calc

Heat per Passenger into Cabin (W)

80

Locked Calc

Locked Calc

Passenger Boundary Temperature (oC)

12

Open/editable

Locked default

Passenger Density: Low Floor (Pass/m^2)

3

Locked Calc

Locked default

Passenger Density: Semi Low Floor (Pass/m^2)

2.2

Locked Calc

Locked default

Passenger Density: Raised Floor (Pass/m^2)

1.4

Locked Calc

Locked default

Calculated Passenger Number

Calculation

Locked Calc

Locked Calc

U-Values W/(K*m^3)

Calculation

Locked Calc

Locked Calc

Heating Boundary Temperature (oC)

18

Open/editable

Locked default

Cooling Boundary Temperature (oC)

23

Open/editable

Locked default

Temperature at which cooling turns OFF

17

Locked default

 

High Ventilation (l/h)

20

Open/editable

Locked default

How Ventilation (l/h)

7

Open/editable

Locked default

High (m^3/h)

Calculation

Locked Calc

Locked Calc

low (m^3/h)

Calculation

Locked Calc

Locked Calc

High Vent Power (W)

Calculation

Locked Calc

Locked Calc

Low Vent Power (W)

Calculation

Locked Calc

Locked Calc

Specific Ventilation Power (Wh/m3)

0.56

Open/editable

Locked default

Aux. Heater Efficiency

0.84

Open/editable

Locked default

GCV (Diesel / Heating oil) (kwh/kg)

11.8

Open/editable

Locked default

Window Area per Unit Bus Length (m^2/m)

Calculation

Locked Calc

Locked Calc

Front + Rear Window Area (m^2)

Calculation

Locked Calc

Locked Calc

Max Temperature Delta for low Floor Busses (K)

3

Open/editable

Locked default

Max Possible Benefit from Technology List (Fraction)

0.5

Open/editable

Locked default

INP - Other

 

 

 

Enviromental Conditions

 

 

 

Enviromental Temperature (oC)

25

Open/editable

Locked default

Solar (W/m²)

400

Open/editable

Locked default

Batch-mode

ON

Open/editable

Locked default

Environmental Conditions Database

TBC Default

Open/editable

Locked default

AC-system

 

 

 

AC-compressor type

2-stage (0/100)

Open/editable

Open/OEM data

AC-compressor type (Mechanical / Electrical)

Calculation

Locked Calc

Locked Calc

AC-compressor capacity (kW)

18

Open/editable

Locked default

COPCool

3.50

Locked Calc

Locked Calc

Ventilation

 

 

 

Ventilation during heating

Yes

Open/editable

Locked default

Ventilation when both Heating and  AC are inactive

Yes

Open/editable

Locked default

Ventilation during AC

Yes

Open/editable

Locked default

Ventilation flow setting when both Heating and  AC are inactive

High

Open/editable

Locked default***

Ventilation during Heating

High

Open/editable

Locked default***

Ventilation during Cooling

High

Open/editable

Locked default***

Aux. Heater

 

 

 

Fuel Fired Heater (kW)

30

Open/editable

Open/OEM data

Input List of Technologies

 

 

 

Insulation

 

 

 

Double-glazing

TF5 table*

Open/editable

Tick box only

Tinted windows

TF5 table*

Open/editable

Tick box only

Ventilation

 

 

 

Fan controll strategy

TF5 table*

Open/editable

Tick box only

Heating

 

 

 

Heat pump systems

TF5 table*

Open/editable

Tick box only

Adjustable coolant thermostat

TF5 table*

Open/editable

Tick box only

Adjustable auxiliary heater

TF5 table*

Open/editable

Tick box only

Engine waste-gas heat exchanger

TF5 table*

Open/editable

Tick box only

Cooling

 

 

 

Separate air distribution ducts

TF5 table*

Open/editable

Tick box only

 

Notes: * Default parameter values for Technology List from ACEA TF5 proposal




** Tinted Window: G-Factor/g-value (= “solar factor” = “total solar energy transmittance”) according ISO 9050

     ISO 9050 defines wind speed at the outside surface of 14 km/h.

 

Definition of bins for transmission rates according to ACEA TF5 recommendation:

g-value

bonus

< 0,1

To be simulated with g = 0,05

0,11 – 0,20

To be simulated with g = 0,15

0,21 – 0,30

To be simulated with g = 0,25

0,31 – 0,40

To be simulated with g = 0,35

0,41 – 0,50

To be simulated with g = 0,45

0,51 – 0,60

To be simulated with g = 0,55

0,61 – 0,70

To be simulated with g = 0,65

0,71 – 0,80

To be simulated with g = 0,75

0,81 – 0,90

To be simulated with g = 0,85

0,91 - 1

To be simulated with g = 0,95

 

*** Air Flow Rate: recommended for future implementation in Declaration mode by ACEA TF5:

Phase

With thermal comfort roof mounted system

Without thermal comfort roof mounted system

Cooling

High (20x internal volume / h)

Low (7x internal volume / h)

Ventilation

High (20x internal volume / h)

Low (7x internal volume / h)

Heating

High (10x internal volume / h)

Low (7x internal volume / h)



File Format


The HVAC SSM (.ahsm) and Bus Parameter Database (.abdb) files use the VECTO CSV format.


Controls



 Open file browser for the HVAC SSM file (.ahsm) or Bus Parameter Database (.abdb) files

 View file contents or navigate to folder

 Tick box to activate/deactivate certain options from the list

 Add button to add a newly defined technology option to the list

 Delete button to remove technology options from the list

 Clear Form button


 Save and close file


Cancel Cancel without saving