• Stabicad for Revit now provides comprehensive support for district heating systems within the heating calculation module!



This update enables Stabicad to support the UK standard CP1, which outlines guidelines for modern and sustainable heat networks. Users can now calculate secondary heat networks according to the diversity rules specified in CP1.



While Stabicad previously supported the calculation and sizing of tertiary heat networks, this enhancement extends its capabilities to include secondary heat networks, offering a more complete solution for district heating projects.

To facilitate the calculation of secondary heat networks, a new heating consumer type, Heat Interface Unit (HIU), has been added. You can easily place the HIU directly via the Stabicad palette, enabling accurate design and calculation for these systems.

The newly introduced HIU is designed to represent an entire apartment, dwelling, or even multiple dwellings within a calculation. It includes specific calculation properties to accurately simulate the heat demands of these spaces.

Relevant Revit parameters have also been integrated to support the new functionality, ensuring seamless data flow and accurate modeling.

To create a calculable system with Heat Interface Units (HIUs), users connect them in the same manner as a regular consumer. This allows for straightforward system design, as demonstrated by an example system featuring three connected HIUs.

When initiating a heating calculation, users now have the option to apply CP1 (2020) diversification by checking the "Diversify loads according to CP1 (2020)" checkbox. Activating this option enables the system to recognize Heat Interface Units (HIUs) and calculate the system as a secondary heat network, ensuring compliance with UK standards.

When a heating calculation is run with CP1 enabled, the report now provides more detailed and transparent information, allowing users to fully understand the results of their secondary heat network designs.

• The Parameters & Settings section of the report clearly specifies that CP1 was applied under Options. It also details the various constants that were used in the calculation, providing full transparency on how the results were derived.

• Heat Interface Units (HIUs) are now specifically listed in the Input and Output Devices section, making it easy to review their role in the system.

• While there are no visual changes to the heating calculation output section, users can be confident that all displayed values have been accurately calculated according to CP1 rules.
• A new, dedicated page titled CP1 volume flow calculation has been added to the report. This page provides a detailed breakdown of the results specific to the CP1 calculation, offering comprehensive insights into the secondary heat network's performance.

The new CP1 volume flow calculation page in the report provides a detailed breakdown of the calculations specific to secondary heat networks. Here's an explanation of each column:

• Consumer / Section: This column remains unchanged from previous reports. CP1 does not introduce new section-breaking elements, and Heat Interface Units (HIUs) are numbered as standard consumers.
• Dwellings Served: This value is derived directly from the HIU input parameters. For each section, it represents the sum of the Dwellings Served parameter from all HIUs connected to that section.
• ΣQSH Sum space heating demand: This figure is taken from the HIU input parameters and represents the sum of the 'Undiversified Space Heating Demand' from all HIUs feeding into a given section. Please note that the input power from any other consumer types (i.e., not HIUs) connected to the section is not included here.
• Heating diversity factor: This factor is calculated for each section using the specific formula outlined in the CP1 standard.
• Diversified space heating flow rate: This is the calculated space heating flow rate for each section, determined by the formula specified in CP1.
• Sum DHW flow ∑qf: This value comes from the HIU input parameters and represents the sum of the 'Undiversified DHW Demand' from all HIUs feeding into the section.
• DHW diversity factor: This factor is calculated by dividing the Diversified DHW Flow by the Sum DHW Flow.
• Diversified DHW flow rate qd: This is the calculated diversified DHW flow rate for each section, based on the formula provided in CP1.
• Combined diversified flow rate: This is the sum of the Diversified DHW flow rate qd and the Diversified space heating flow rate. It's important to note that this value does not include any flows or power from other types of consumers (anything other than HIUs).
• Calculation volume flow: This is the total flow used for pressure loss and velocity computations in the section output report. It's calculated by summing the Diversified DHW flow rate qd, the Diversified space heating flow rate, and the volume flow from other types of equipment (non-HIU). If your model only contains HIUs, the Calculation volume flow and the Combined diversified flow rate will be identical.



When a heating calculation is performed with CP1 enabled, the interactive results dialog now includes several new columns within the heating section:

• The heating section of the interactive results dialog now features several new columns, mirroring the detailed information provided in the CP1 report. Users can easily customize their view and focus on specific data by utilizing the Column Chooser feature, conveniently located next to the search bar.

• Within the devices section, Heat Interface Units (HIUs) are now specifically identified and listed in the Type column. This allows users to easily distinguish HIUs from other equipment at a glance, improving clarity and organization.

Upon successful completion of a calculation with CP1 enabled, several new Revit shared parameters are automatically added to pipes. These parameters provide additional data crucial for detailed analysis and documentation of secondary heat networks:

To provide you with greater control over the variables utilized in CP1 calculation formulas, new StabiBASE parameters have been introduced. These additions allow for precise adjustments and fine-tuning of the CP1 calculations, ensuring accuracy and flexibility.

Users should be aware of the following key points when utilizing the new CP1 feature for heating calculations:

• Separate Network Calculations: The system does not support simultaneous calculation of secondary and tertiary heat networks. The Heat Interface Unit (HIU) family is designed without outgoing connectors for directly connecting heating or domestic water appliances.
• Combining HIUs with Regular Consumers: It is possible to use regular consumers (any device that is not an HIU) in conjunction with HIUs when CP1 is enabled. However, only the sections feeding HIUs will have CP1 diversity rules applied. The flow from other, non-HIU consumers will be added as a surplus without diversity.
• Using HIUs Without CP1 Diversity: Users can also incorporate HIUs into calculations without enabling CP1 diversification. In this scenario, HIUs will be treated as standard consumers, and no diversity will be applied to their loads.
• StabiBASE Domestic Water Settings: New settings in StabiBASE related to domestic water do not impact the domestic water calculation itself. To modify these settings, users should navigate to Piping, Calculation, and then Tapwater.
• Online Requirement for CP1: The CP1 feature is exclusively available when CIBSE (Cloud) is selected as the calculation standard in StabiBASE. This means an active internet connection is required to utilize this functionality.
• Local CIBSE Calculation with HIUs: The local CIBSE calculation will also work with HIUs. In this context, HIUs will be treated as regular consumers, and no diversity will be applied to their loads.
• Flexible System Design: It is not mandatory to place a boiler or provider when designing secondary heat networks with CP1. Users can initiate the system with two open ends (one for supply and one for return).

• An error report related to circuit numbering has been addressed. Previously, the application would report an error if a user assigned a circuit number beyond the capacity of the panel board. This has been fixed to prevent the error and ensure smoother workflow when managing circuits.

• New for UK Customers: Stabicad for AutoCAD

This release marks the official launch of Stabicad for AutoCAD in the United Kingdom. To ensure a seamless design experience that aligns with local industry standards, we have introduced several UK-specific features.



Highlights of this localisation include:

• CIBSE Mechanical Diagrams: The CIBSE diagram library has been added to the Palette Centre, bringing it in line with the functionality available in Stabicad for Revit.
• Support for CIBSE Standards: Stabicad for AutoCAD now fully supports CIBSE-specific layers and pipe types, enabling you to create compliant and standardized designs with ease.
• Localized Sanitary Symbols: We have integrated standard UK symbols for sanitary systems, ensuring your drawings are accurate and recognisable.

• Duct Type visualization for calculations

To improve accuracy before calculating ventilation systems, a new visualization feature has been added to the calculation tab. You can now instantly see the duct type assigned to each duct, indicated by green, red, or yellow colors. This allows for a quick and easy check to ensure the correct duct types are set, leading to more reliable calculation results for system sizes and flow.

• Improved Database Connectivity

When selecting a Stabicad database using the "Select Database" function, the newly chosen database and any additional connection string parameters are now correctly written to the drivers.xml.config file. This ensures consistent and reliable database connections.

• Database configuration update

With version 25.07, we are performing a one-time database optimization during the installation process. This procedure will shrink your database size by approximately 50% and rebuild its indexes for efficiency. As a result, you will see a significant speed increase when exporting and importing projects in StabiBASE.



When selecting a Stabicad database using the "Select Database" feature, the newly chosen database and any additional connection string parameters are now recorded in the drivers.xml.config file.



Stabicad 25.07 introduces a significant update to standardize the use of project standards across different localizations. Previously, users could choose between the NL-sfb and CIBSE (UK) standards. Starting with version 25.07, only the Stabicad UK localization will support the CIBSE standard, while all other localizations will exclusively use the NL-SFB standard. This change involves a database clean-up during the update process.



• Updated external links in StabiBASE

External links within the StabiBASE functionality have been updated, providing you with more direct access to support and community resources.