Generating a Heat Load Time Series
For the simulation of energy systems with heat demand, it is useful to specify the heat demand in its temporal changes as a time series in order to take into account the effects of these fluctuations on the entire energy system with its various energy sources, demands, and storage solutions. If there are no sufficient measurements of the heat load over time, you can simply use the ETA to determine the approximate heat load profile for a year, for example, based on the total heat demand. The ETA method calculates the heat load profile on the basis of an outdoor temperature time series and the empirical values stored in the software for various types of demand.
Prerequisites
You need an outdoor temperature time series that specifies the period and the time grid for the heat load profile time series to be generated.
You need the total heat demand for the period covered by the temperature time series. If no measured values are available, estimate this.
Applying the Method
Before starting the method, open the time series of the ambient temperature, on the basis of which the time series of the heat load profile is to be created, in the ETA. Then invoke the Heat load generation method using the 
button in the Project ribbon in the New time series group (see following figure).
Alternatively, invoke the method via the context menu of the temperature time series in the Project explorer under Methods → Convert time series (see following figure).
The following dialog box opens.
First select the temperature time series from the time series opened in the ETA. It is the basis for the heat load profile. Select a concrete temperature time series. The method only works with concrete and not abstract time series because concrete points in time have to be specified. Temperatures above 40 °C are reduced to 40 °C during the calculation in order to determine results for the daily values in accordance with the calculation rules.
Type
Based on the type, usage behavior, heating and hot water consumption, shares of process and heating energy, building types, fluctuations due to the time of day, the day of the week, and the season are included in the calculation, for example in the form of profile factors, coefficients, standardized hourly values (hour factors), and day-of-the-week-factors.
Select the Type of heat demand from the drop-down list. The Type designations available for selection each consist of a German abbreviation and a typical representative or typical representatives, which stand for a much wider range of applications. The three-letter abbreviation begins with H for household or G for commercial (German: Gewerbe), followed by the two-letter abbreviation for the representative. The Description below lists which applications the respective type is suitable for, among other things, for example households or businesses with certain properties that can go far beyond the narrow type designation. The Types available for selection and examples of their applications are listed below.
The method is based on the dissertation “Entwicklung und Anwendung parametrisierter Standard-Lastprofile” by Mark Hellwig at the Technische Universität München from 2003 (https://mediatum.ub.tum.de/doc/601557/601557.pdf), which breaks down the consumption types by category and lists the associated factors and confidence intervals individually, and the following program:
Frolova, Kirena; te Heesen, Henrik (2023). Synthese von Wärmelastprofilen nach BDEW (Version from November 1, 2023) [computer program]. Hochschule Trier. Available under: umwelt-campus.de/energietools (retrieved February 1, 2024).
The synthesis is based on the DEW/VKU/GEODE-Leitfaden Abwicklung von Standardlastprofilen Gas (guidelines for the processing of standard gas load profiles). The individual load profile types have different temperature dependencies.
The following diagrams show the different temperature dependencies of the individual load profile types, depending on the heating and process gas dependency. The first diagram illustrates the heating and process gas dependency of the load profile types selected as examples.
Heating Versus Process Gas Dependency of Different Load Profile Types
The following diagram illustrates the different temperature dependencies and the different peak loads of the individual load profile types.
Normalized Value of the Daily Quantity h (h=1 at 8 °C) as a Function of the Outside Temperature
The higher the proportion of heating gas and the lower the proportion of process gas, the greater the temperature dependency and the higher the peak loads of the load profile. This is also illustrated in Figures 14 and 15 in the guidelines “BDEW/VKU/GEODE-Leitfaden Abwicklung von Standardlastprofilen Gas”, published by the BDEW Bundesverband der Energie- und Wasserwirtschaft e. V., Verband kommunaler Unternehmen e. V. (VKU), and GEODE – Groupement Européen des entreprises et Organismes de Distribution d’Énergie, EWIV, on March 29, 2018 (https://www.vku.de/fileadmin/user_upload/Verbandsseite/Sparten/Energiewirtschaft/Gasthemen/nach_Leitfaden_SLP.pdf, retrieved March 14, 2024). It contains detailed information on the types and characteristics of the profiles used and the formulas for their calculation.
Subtype
The Subtype indicates the characteristics of the load profile in accordance with the specifications of the Sigmoid function used for gas load profiles by the Technische Universität München (TUM) and the linearized SigLinDe function of the Forschungsgesellschaft für Energiewirtschaft, München (FfE). The latter merges the Sigmoid function with the heating line and the hot water line, thus achieving greater sharpness in the transition area from the heating to the hot water phase and compensating errors in the pure Sigmoid function at cold temperatures and during hot water consumption in summer. The first digit of the Subtype indicates the source: 0 stands for Sigmoid according to TUM, 3 for SigLinDe according to FfE. The second digit of the Subtype represents the characteristics of the load profile according to the proportions of heating and process gas: 1 stands for a high proportion of process gas, 2 only for an increased proportion of process gas, 3 for a medium, 4 for an increased, and 5 for a high proportion of heating gas related to the profile Type. Profiles 33 and 34 correspond to further developed variants of characteristics 03 and 04. The following Subtypes are available for selection:
Integral
Enter the Integral of the heat required over the entire period of the temperature time series and the corresponding Unit, for example kWh.
Performing
To execute the method, click on the OK button at the bottom of the dialog window.
Result Time Series
The result time series is given the name Heat Load. If there is already a time series of the same name in the Project explorer, a number in brackets is added to the name of the newly created time series. The more Heat Load time series already exist, the higher the number, starting with 1, e.g., Heat Load (1), Heat Load (2), etc. The unit of the heat load time series, for example kW, is derived from that of the integral. The time period and temporal resolution correspond to those of the temperature time series. For example, if it is available in 15-minute steps, the result time series will also have a step width (Sample time) of 15 minutes. Transfer the result time series to the TOP-Energy project and use it for simulations there.
