H2 knowledge space: Energy design tool for private households

The influence of hydrogen as an energy storage medium will become increasingly important. Its use in private households is still heavily dependent on the given boundary conditions and is therefore only used in isolated cases. With our experience from various projects for industrial partners and the municipality of Nebelschütz in Upper Lusatia, we have been able to develop a comprehensive library for planning such energy storage systems. This enables the automated technical design of energy storage systems with hydrogen and battery storage systems as well as a subsequent economic evaluation. We consider the entire chain - from determining the consumers and the potential from photovoltaics and wind power to dimensioning and calculating the respective storage system. We determine the existing boundary conditions and develop a suitable solution for the respective project. 

In order to make this knowledge more easily available to private households, we offer ARON (Automated Renewable hOmepower Network) offers a free design tool for single-family homes, the operation of which is explained below. This tool is only used to estimate the possible energy quantities and an economic assessment of the system. Under no circumstances does it replace an offer or advice from a specialist company.

The calculations are always based on the values of a “typical meteorological year” (TMY for short), which are determined by the PVGIS-TOOL of the European Union. To do this, you must first enter the coordinates and the height of the location of the detached house  (step 1 in input window).

The photovoltaic system (PV for short) is defined in the next area (step 2 in the input window). Each module is defined by its maximum output, the orientation in the respective cardinal direction [South - S (180°), East - E (90°), West - W (270°), SO - South East (135°), SSO - South South East (157.5°) etc.] and its angle of attack (0° - horizontal, 90° - vertical etc.). Additional modules can be added by activating the checkbox. The maximum total permissible output is 30 kWp.

Finally, enter the investment costs for your PV system and the remuneration for one kilowatt hour fed back into the grid. The inflation value describes the possible annual increase in this remuneration. If you do not receive any remuneration, set both values to zero. For the investment costs, you should definitely consider any subsidies from the KfW, the BMWK or the SAB and deduct it independently from the investment sum. To determine the photovoltaic potential of your household, you can easily check this for your property (only for Saxony) in SAENA's solar register.

The electricity consumption of your household is determined in the next section. To do this, enter your annual electricity consumption as well as your current household electricity tariff per kilowatt hour and the estimated annual cost increase (inflation) on this tariff here (step 3 in the input window). If you have already installed a heat pump, the consumption will be calculated separately in the next section. This can be deducted here.

The optional calculation of a heat pump can be activated in the next section by ticking the checkbox (step 4 in the input window). This requires several details about your house and your heating system. Enter the output of your heating system (maximum 30 kW), the desired heat pump type and the refurbishment status of your house (e.g. KfW 85 - 15% better insulated house than the reference building defined by KfW). The annual heat consumption (maximum 60 MWh) and the type of radiator are then requested. The number of people in the household must be specified in order to estimate the hot water consumption. Finally, enter the investment costs, the previous heating costs with the current heating system and the annual inflation rate for the previous heat source. Take any subsidies into account here too.

The battery calculation can also be activated via the checkbox (step 5 in the input window). The battery capacity (maximum 30 kWh) and the investment costs are the only information required for the calculation. The battery size can also be calculated automatically if the corresponding checkbox is activated. Subsidies are also possible here.

Finally, the calculation is started in the last area (step 6 in the input window) by clicking on the corresponding button. To estimate all investment costs, click on the “Estimate costs” button. If incorrect entries are made, the values are automatically updated and the incorrect fields are also indicated on the left. 

The language of the input and output window can be changed by pressing the “English” button.

All entries are saved temporarily in a configuration file. Previous data can be loaded by clicking on the “Load config” button. This file is overwritten when a new calculation is performed.

The most important results are displayed in the evaluation window using diagrams or a brief summary. 

Link to the design tool

As the software is released as a free demonstration tool, it is unfortunately not possible to provide full support. We will endeavor to answer all inquiries. 

This tool requires a WINDOWS operating system and a screen with HD resolution is recommended, lower resolutions will still work.

The font display is set for 100 % scaling. (Windows settings / Screen / Scaling and arrangement / 100 % (recommended))

This tool is only intended to estimate the possible energy quantities and to provide an economic assessment of the system. Under no circumstances does it replace an offer or advice from a specialist company. The size of the application is due to the libraries used and the export from Python to an executable file. 

Version v.016

Data from PVGIS-Tool, which obtains data for the respective location via an interface, serves as the basis. All calculations are based on the irradiation values and temperature data for a typical meteorological year. This means that both better and worse years are possible for the defined system. All calculations are based on hourly values, which are summarized as monthly values for illustrative purposes.

The photovoltaic system is calculated using modules from the pvlib library.

BDEW profiles for households are used to calculate the annual consumption, which are scaled based on the annual consumption [1].

The bivalence curve is assumed to be a simplified linear curve from 100% heating output at -15 °C to 0% at 20 °C. The bivalence point is 70% of the rated output. Furthermore, the heat pump is calculated using the COP curves shown in the diagram. The radiator system and the refurbishment status of the building are classified using various assumed heating curves and their K-factors (see matrix below):

In addition, the daily heating profiles are calculated using standard load profiles for the daily heat demand [2]. A daily hot water demand of 1.8 kWh is assumed for each person in the household.

The following Python libraries are used: pvlib, pandas, numpy, matplotlib, scipy, tkinter, screeninfo, configparser.

References:

1. R. T. Dr. C. Fünfgeld, »BDEW Standardlastprofile Strom« [Online]. Available: https://www.bdew.de/energie/standardlastprofile-strom. [Zugriff am 04.09.2023].
2. O. Ruhnau, L. Hirth, A. Praktiknjo »Time series of heat demand and heat pump efficiency for energy system modeling«, 2019, www.Nature.com/scientificdata

Release notes:

The new version fixes some problems caused by main screens with a resolution lower than HD.

In addition, this version is now also executable in English and offers the option of reloading the last previous input when running it later.