heatbeat Research Newsletter
Published on the first Wednesday of each month, our heatbeat Research Newsletter features a selected research article from the research fields of district heating, district cooling and district energy systems. We summarize the research work and highlight the most important findings. This way you can easily keep track of the current trends and innovations in these subject areas and stay updated about the current state of the art. All issues are freely available on this page. Furthermore you can subscribe to conveniently receive the the newsletter straight to your email inbox. For this, you can choose between an English or the German version:
we are happy to present to you the second edition of our heatbeat Research Newsletter. In our first issue we looked into the integration of waste heat and solar thermal energy into district heating networks. In this issue we shift our focus to the demand side, where heat demands for domestic hot water (DHW) play an increasingly important role. The paper we selected for this issue explores methods to generate realistic DHW load profiles investigates the influence of different substation types on DHW demands, losses, and return temperatures.
We dedicate our second issue to the paper District heating load profiles for domestic hot water preparation with realistic simultaneity using DHWcalc and TRNSYS by Hagen Braas et al. from the Department of Solar and Systems Engineering of the Institute of Thermal Engineering at the University of Kassel. It presents methods to model the heat demand for domestic hot water preparation in district heating networks with realistic load profiles and simultaneities. In addition, it examines different substation types and their influence on the return temperatures for the district heating network.
On the one hand, the results show that domestic hot water profiles with realistic simultaneity factors can be generated with the free software DHWcalc. On the other hand, simulations of the substations show that a direct preparation of domestic hot water can achieve lower average return temperatures than systems using a DHW storage in the building. At the same time, as expected, there are significantly higher peak loads without a storage. The paper also shows the relation between heat demand and distribution and storage losses for all investigated variants.
From our point of view, the researchers are addressing an important topic in the analysis of district heating networks. In many cases, static load values are not sufficient for the interpretation and the evaluation of the network operation. The paper offers solutions for this by generating individual stochastic tap profiles for each building. In addition, the paper analyzes the DHW heat demands and heat losses as well as the simultaneity factors in detail and compares the results with other sources. The work thus provides good reference values for further applications.
The paper District heating load profiles for domestic hot water preparation with realistic simultaneity using DHWcalc and TRNSYS by Hagen Braas et al. addresses important questions about the influence of the domestic hot water demand in investigations and evaluations of district heating networks. Especially when considering the decreasing space heating demand due to higher building insulation standards and milder winters, the DHW demand is playing an increasingly important role. In this research paper, a special focus is placed on three aspects:
As the title of the paper already indicates, the researchers work with the two software solutions DHWcalc and TRNSYS. DHWcalc is free software that is developed at the Department of Solar and Systems Engineering of the Institute of Thermal Engineering at University of Kassel and is offered as a free download. This software has already been described to be a well-suited solution for the generation of domestic hot water profiles in several scientific publications. With these profiles, natural variations of the tap water discharge can be modelled realistically.
With the simulation software TRNSYS the authors model different substation designs. These models take the tap profiles created with DHWcalc as input data and simulate the operation of the substations and their interactions with the district heating network. Of particular interest are the return temperatures that can be achieved at given supply temperatures with different substation designs.
The authors model and simulate 4 different substation designs for heat transfer between the network and buildings. A distinction is made between substations for single-family houses and for multi-family houses. These models differ mainly in the single-family house being connected to the district heating network with a single heat exchanger, while the substations for the multi-family house have 2 heat exchangers. By dividing the heat exchange into a pre-heater and an after-heater, the network return temperature can be lowered when the building system is in circulation mode in order to achieve greater efficiency. One variant with and one without DHW storage is analyzed for both the single-family house and the multi-family house. For all 4 variants, a constant supply temperature from the district heating network of 70 °C is used.
With this setup, the paper yields interesting results for the various investigated variants: From the simulations, the researchers determine specific DHW heat demands between 8.5 and 11 kWh/m²a for different single-family houses. The values for the considered multi-family houses lie between 11.7 and 12.5 kWh/m²a. In relation to this, the simulations determine distribution losses in the building of 8 - 13 kWh/m²a. In the variants with DHW storage, the storage losses vary significantly, with values up to 14 kWh/m²a for small single-family houses ranging to below 1 kWh/m²a for larger multi-family houses.
In addition to these values for demands and losses, the paper also analyzes the return temperatures that can be achieved for the various substation designs. The paper shows that the substations without a DHW storage can achieve annual averages for the return temperatures that are around 8 - 9 K lower than for the substations with a DHW storage. As further means to achieve lower return temperatures, the researchers mention stronger pipe insulation in the building and avoiding the circulating of hot water, which leads to high return temperatures during reheating.
Another important aspect of the paper is the simultaneity of DHW demands in a district and the influence of different substation designs on the peak loads. For a small single-family house without a DHW storage, the main DHW heat demand is determined to cover less than 300 hours in the annual duration curve, while the circulation mode extends over about 6000 hours. While, as already mentioned, lower return temperatures can be achieved for the system without DHW storage, a peak load of 42 kW is specified for this variant. In contrast, a peak load of 3 kW is found to be sufficient when the storage is charged under ideal conditions in the model.
With regard to simultaneity, the paper shows a comparison between its own results and different values from the relevant literature for single-family houses with and without DHW storage. Consistent with the values from the relevant literature, it can be seen that the simultaneity factor with storage decreases from the initial value of 100 % for one building to about 40 - 50 % for 20 buildings and to about 30 - 45 % for 100 buildings. Without storage, the effects are more pronounced with a factor of around 15 - 20 % for 20 buildings and simultaneities of around 10 % for 100 buildings. In addition, the investigation shows that on hourly resolutions the results change significantly compared to the original resolution of 3 minute intervals and thus the selected frequency has a strong influence on the results.
From our point of view, the paper shows a good overview and many interesting aspects for the evaluations of DHW demands in the context of district heating networks. Even though the demand for space heating is not considered in this paper, it offers good orientation and many reference values for a holistic view of thermal network operation in a district. And since, as mentioned at the beginning, higher building insulations standards and warmer winters lead to a stronger influence of DHW demands on the network operation, DHW is playing an increasingly important role in such systems. Therefore, these results are of particular importance for the future. Our project experience at heatbeat, in which the influence of the DHW demands in the dynamic simulation and holistic evaluation of district heating networks is increasingly evident, confirms this trend. In our projects, we place a high importance on considering buildings as an integral part of district heating networks. This enables us to consider the interactions between DHW demands, return temperatures and network efficiency in detail.
The original article can be found at https://doi.org/10.1016/j.energy.2020.117552. Further information as well as the free download of DHWcalc and the associated manual can be found on the homepage of the Department of Solar and Systems Engineering. A newer version including features used in the paper is currently in development. For interested parties, the authors offer to provide a pre-release version when contacted via email.
Furthermore, the authors of the presented paper have published another paper titled Systematic investigation of building energy efficiency standard and hot water preparation systems’ influence on the heat load profile of districts from Best et al. It addresses the influence of building insulatinos standards and the type of DHW generation on the heat demand profile of districts in detail.
At the end of this second edition, we would like to invite you again to give us feedback so that the newsletter can offer you the greatest possible value. Do you have any ideas on how we can make the newsletter more valuable to you? Then contact us at email@example.com
The next issue of our newsletter will be released on January 6, 2021.
We are very delighted that you have shown interest in our enterprise. Data protection is of a particularly high priority for the management of the heatbeat engineering GmbH. The use of the Internet pages of the heatbeat engineering GmbH is possible without any indication of personal data; however, if a data subject wants to use special enterprise services via our website,processing of personal data could become necessary. If the processing of personal data is necessary and there is no statutory basis for such processing, we generally obtain consent from the data subject.
The processing of personal data, such as the name, address, e-mail address, or telephone number of a data subject shall always be in line with the General Data Protection Regulation (GDPR), and in accordance with the country-specific data protection regulations applicable to the heatbeat engineering GmbH. By means of this data protection declaration, our enterprise would like to inform the general public of the nature, scope, and purpose of the personal data we collect, use and process. Furthermore, data subjects are informed, by means of this data protection declaration, of the rights to which they are entitled.
As the controller, the heatbeat engineering GmbH has implemented numerous technical and organizational measures to ensure the most complete protection of personal data processed through this website. However, Internet-based data transmissions may in principle have security gaps, so absolute protection may not be guaranteed. For this reason, every data subject is free to transfer personal data to us via alternative means, e.g. by telephone.
The data protection declaration of the heatbeat engineering GmbH is based on the terms used by the European legislator for the adoption of the General Data Protection Regulation (GDPR). Our data protection declaration should be legible and understandable for the general public, as well as our customers and business partners. To ensure this, we would like to first explain the terminology used.
In this data protection declaration, we use, inter alia, the following terms:
Personal data means any information relating to an identified or identifiable natural person (“data subject”). An identifiable natural person is one who can be identified, directly or indirectly, in particular by reference to an identifier such as a name, an identification number, location data, an online identifier or to one or more factors specific to the physical, physiological, genetic, mental, economic, cultural or social identity of that natural person.
Data subject is any identified or identifiable natural person, whose personal data is processed by the controller responsible for the processing.
Processing is any operation or set of operations which is performed on personal data or on sets of personal data, whether or not by automated means, such as collection, recording, organisation, structuring, storage, adaptation or alteration, retrieval, consultation, use, disclosure by transmission, dissemination or otherwise making available, alignment or combination, restriction, erasure or destruction.
Restriction of processing is the marking of stored personal data with the aim of limiting their processing in the future.
Profiling means any form of automated processing of personal data consisting of the use of personal data to evaluate certain personal aspects relating to a natural person, in particular to analyse or predict aspects concerning that natural person's performance at work, economic situation, health, personal preferences, interests, reliability, behaviour, location or movements.
Pseudonymisation is the processing of personal data in such a manner that the personal data can no longer be attributed to a specific data subject without the use of additional information, provided that such additional information is kept separately and is subject to technical and organisational measures to ensure that the personal data are not attributed to an identified or identifiable natural person.
Controller or controller responsible for the processing is the natural or legal person, public authority, agency or other body which, alone or jointly with others, determines the purposes and means of the processing of personal data; where the purposes and means of such processing are determined by Union or Member State law, the controller or the specific criteria for its nomination may be provided for by Union or Member State law.
Processor is a natural or legal person, public authority, agency or other body which processes personal data on behalf of the controller.
Recipient is a natural or legal person, public authority, agency or another body, to which the personal data are disclosed, whether a third party or not. However, public authorities which may receive personal data in the framework of a particular inquiry in accordance with Union or Member State law shall not be regarded as recipients; the processing of those data by those public authorities shall be in compliance with the applicable data protection rules according to the purposes of the processing.
Third party is a natural or legal person, public authority, agency or bodyother than the data subject, controller, processor and persons who, under the direct authority of the controller or processor, are authorised to process personal data.
Consent of the data subject is any freely given, specific, informed and unambiguous indication of the data subject's wishes by which he or she, by a statement or by a clear affirmative action, signifies agreement to the processing of personal data relating to him or her.
Controller for the purposes of the General Data Protection Regulation (GDPR), other data protection laws applicable in Member states of the European Union and other provisions related to data protection is:heatbeat engineering GmbH
The website of heatbeat engineering GmbH uses the internet service plausible (https://plausible.io/). This allows heatbeat engineering GmbH certain statistics view the website usage and at the same time privacy not compromise our users. No cookies are set and IP addresses are never saved. For exact information what data is provided by plausible please refer to https://plausible.io/data-policy.
The website of the heatbeat engineering GmbH collects a series of general data and information when a data subject or automated system calls up the website. This general data and information are stored in the server log files. Collected may be (1) the browser types and versions used, (2) the operating system used by the accessing system, (3) the website from which an accessing system reaches our website (so-called referrers), (4) the sub-websites, (5) the date and time of access to the Internet site, (6) an Internet protocol address (IP address), (7) the Internet service provider of the accessing system, and (8) any other similar data and information that may be used in the event of attacks on our information technology systems.
When using these general data and information, the heatbeat engineering GmbH does not draw any conclusions about the data subject. Rather, this information is needed to (1) deliver the content of our website correctly, (2) optimize the content of our website as well as its advertisement, (3) ensure the long-term viability of our information technology systems and website technology, and (4) provide law enforcement authorities with the information necessary for criminal prosecution in case of a cyber-attack. Therefore, the heatbeat engineering GmbH analyzes anonymously collected data and information statistically, with the aim of increasing the data protection and data security of our enterprise, and to ensure an optimal level of protection for the personal data we process. The anonymous data of the server log files are stored separately from all personal data provided by a data subject.
The website of the heatbeat engineering GmbH contains information that enables a quick electronic contact to our enterprise, as well as direct communication with us, which also includes a general address of the so-called electronic mail (e-mail address). If a data subject contacts the controller by e-mail or via a contact form, the personal data transmitted by the data subject are automatically stored. Such personal data transmitted on a voluntary basis by a data subject to the data controller are stored for the purpose of processing or contacting the data subject. There is no transfer of this personal data to third parties.
The data controller shall process and store the personal data of the data subject only for the period necessary to achieve the purpose of storage, or as far as this is granted by the European legislator or other legislators in laws or regulations to which the controller is subject to.
If the storage purpose is not applicable, or if a storage period prescribed by the European legislator or another competent legislator expires, the personal data are routinely blocked or erased in accordance with legal requirements.
Each data subject shall have the right granted by the European legislator to obtain from the controller the confirmation as to whether or not personal data concerning him or her are being processed. If a data subject wishes to avail himself of this right of confirmation, he or she may, at any time, contact any employee of the controller.
Each data subject shall have the right granted by the European legislator to obtain from the controller free information about his or her personal data stored at any time and a copy of this information. Furthermore, the European directives and regulations grant the data subject access to the following information:
Furthermore, the data subject shall have a right to obtain information as to whether personal data are transferred to a third country or to an international organisation. Where this is the case, the data subject shall have the right to be informed of the appropriate safeguards relating to the transfer.
If a data subject wishes to avail himself of this right of access, he or she may, at any time, contact any employee of the controller.
Each data subject shall have the right granted by the European legislator to obtain from the controller without undue delay the rectification of inaccurate personal data concerning him or her. Taking into account the purposes of the processing, the data subject shall have the right to have incomplete personal data completed, including by means of providing a supplementary statement.
If a data subject wishes to exercise this right to rectification, he or she may, at any time, contact any employee of the controller.
Each data subject shall have the right granted by the European legislator to obtain from the controller the erasure of personal data concerning him or her without undue delay, and the controller shall have the obligation to erase personal data without undue delay where one of the following grounds applies, as long as the processing is not necessary:
If one of the aforementioned reasons applies, and a data subject wishes to request the erasure of personal data stored by the heatbeat engineering GmbH, he or she may, at any time, contact any employee of the controller. An employee of heatbeat engineering GmbH shall promptly ensure that the erasure request is complied with immediately.
Where the controller has made personal data public and is obliged pursuant to Article 17(1) to erase the personal data, the controller, taking account of available technology and the cost of implementation, shall take reasonable steps, including technical measures, to inform other controllers processing the personal data that the data subject has requested erasure by such controllers of any links to, or copy or replication of, those personal data, as far as processing is not required. An employees of the heatbeat engineering GmbH will arrange the necessary measures in individual cases.
Each data subject shall have the right granted by the European legislator to withdraw his or her consent to processing of his or her personal data at any time.
If one of the aforementioned conditions is met, and a data subject wishes to request the restriction of the processing of personal data stored by the heatbeat engineering GmbH, he or she may at any time contact any employee of the controller. The employee of the heatbeat engineering GmbH will arrange the restriction of the processing.
Each data subject shall have the right granted by the European legislator, to receive the personal data concerning him or her, which was provided to a controller, in a structured, commonly used and machine-readable format. He or she shall have the right to transmit those data to another controller without hindrance from the controller to which the personal data have been provided, as long as the processing is based on consent pursuant to point (a) of Article 6(1) of the GDPR or point (a) of Article 9(2) of the GDPR, or on a contract pursuant to point (b) of Article 6(1) of the GDPR, and the processing is carried out by automated means, as long as the processing is not necessary for the performance of a task carried out in the public interest or in the exercise of official authority vested in the controller.
Furthermore, in exercising his or her right to data portability pursuant to Article 20(1) of the GDPR, the data subject shall have the right to have personal data transmitted directly from one controller to another, where technically feasible and when doing so does not adversely affect the rights and freedoms of others.
In order to assert the right to data portability, the data subject may at any time contact any employee of the heatbeat engineering GmbH.
Each data subject shall have the right granted by the European legislator to object, on grounds relating to his or her particular situation, at any time, to processing of personal data concerning him or her, which is based on point (e) or (f) of Article 6(1) of the GDPR. This also applies to profiling based on these provisions.
The heatbeat engineering GmbH shall no longer process the personal data in the event of the objection, unless we can demonstrate compelling legitimate grounds for the processing which override the interests, rights and freedoms of the data subject, or for the establishment, exercise or defence of legal claims.
If the heatbeat engineering GmbH processes personal data for direct marketing purposes, the data subject shall have the right to object at any time to processing of personal data concerning him or her for such marketing. This applies to profiling to the extent that it is related to such direct marketing. If the data subject objects to the heatbeat engineering GmbH to the processing for direct marketing purposes, the heatbeat engineering GmbH will no longer process the personal data for these purposes.
In addition, the data subject has the right, on grounds relating to his or her particular situation, to object to processing of personal data concerning him or her by the heatbeat engineering GmbH for scientific or historical research purposes, or for statistical purposes pursuant to Article 89(1) of the GDPR, unless the processing is necessary for the performance of a task carried out for reasons of public interest.
In order to exercise the right to object, the data subject may contact any employee of the heatbeat engineering GmbH. In addition, the data subject is free in the context of the use of information society services, and notwithstanding Directive 2002/58/EC, to use his or her right to object by automated means using technical specifications.
Each data subject shall have the right granted by the European legislator not to be subject to a decision based solely on automated processing, including profiling, which produces legal effects concerning him or her, or similarly significantly affects him or her, as long as the decision (1) is not is necessary for entering into, or the performance of, a contract between the data subject and a data controller, or (2) is not authorised by Union or Member State law to which the controller is subject and which also lays down suitable measures to safeguard the data subject's rights and freedoms and legitimate interests, or (3) is not based on the data subject's explicit consent.
If the decision (1) is necessary for entering into, or the performance of, a contract between the data subject and a data controller, or (2) it is based on the data subject's explicit consent, the heatbeat engineering GmbH shall implement suitable measures to safeguard the data subject's rights and freedoms and legitimate interests, at least the right to obtain human intervention on the part of the controller, to express his or her point of view and contest the decision.
If the data subject wishes to exercise the rights concerning automated individual decision-making, he or she may, at any time, contact any employee of the heatbeat engineering GmbH.
Each data subject shall have the right granted by the European legislator to withdraw his or her consent to processing of his or her personal data at any time.
If the data subject wishes to exercise the right to withdraw the consent, he or she may, at any time, contact any employee of the heatbeat engineering GmbH.
The data controller shall collect and process the personal data of applicants for the purpose of the processing of the application procedure. The processing may also be carried out electronically. This is the case, in particular, if an applicant submits corresponding application documents by e-mail or by means of a web form on the website to the controller. If the data controller concludes an employment contract with an applicant, the submitted data will be stored for the purpose of processing the employment relationship in compliance with legal requirements. If no employment contract is concluded with the applicant by the controller, the application documents shall be automatically erased two months after notification of the refusal decision, provided that no other legitimate interests of the controller are opposed to the erasure. Other legitimate interest in this relation is, e.g. a burden of proof in a procedure under the General Equal Treatment Act (AGG).
Art. 6(1) lit. a GDPR serves as the legal basis for processing operations for which we obtain consent for a specific processing purpose. If the processing of personal data is necessary for the performance of a contract to which the data subject is party, as is the case, for example, when processing operations are necessary for the supply of goods or to provide any other service, the processing is based on Article 6(1) lit. b GDPR. The same applies to such processing operations which are necessary for carrying out pre-contractual measures, for example in the case of inquiries concerning our products or services. Is our company subject to a legal obligation by which processing of personal data is required, such as for the fulfillment of tax obligations, the processing is based on Art. 6(1) lit. c GDPR. In rare cases, the processing of personal data may be necessary to protect the vital interests of the data subject or of another natural person. This would be the case, for example, if a visitor were injured in our company and his name, age, health insurance data or other vital information would have to be passed on to a doctor, hospital or other third party. Then the processing would be based on Art. 6(1) lit. d GDPR.
Where the processing of personal data is based on Article 6(1) lit. f GDPR our legitimate interest is to carry out our business in favor of the well-being of all our employees and the shareholders.
The criteria used to determine the period of storage of personal data is the respective statutory retention period. After expiration of that period, the corresponding data is routinely deleted, as long as it is no longer necessary for the fulfillment of the contract or the initiation of a contract.
We clarify that the provision of personal data is partly required by law (e.g. tax regulations) or can also result from contractual provisions (e.g. information on the contractual partner). Sometimes it may be necessary to conclude a contract that the data subject provides us with personal data, which must subsequently be processed by us. The data subject is, for example, obliged to provide us with personal data when our company signs a contract with him or her. The non-provision of the personal data would have the consequence that the contract with the data subject could not be concluded. Before personal data is provided by the data subject, the data subject must contact any employee. The employee clarifies to the data subject whether the provision of the personal data is required by law or contract or is necessary for the conclusion of the contract, whether there is an obligation to provide the personal data and the consequences of non-provision of the personal data.
As a responsible company, we do not use automatic decision-making or profiling.
According to § 5 TMGheatbeat engineering GmbH
Dr.-Ing. Marcus Fuchs
Registration in the commercial register.
Register court: Nürnberg
Registration number: 35347
VAT identification number according to §27a sales tax law: DE314956332
Registration in the commercial register.
Register court: Aachen
Registration number: 23912
VAT identification number according to §27a sales tax law: DE332454341
Liability for content
The contents of our pages were created with great care. For the accuracy, completeness and timeliness of the contents, however, we can not guarantee. As a service provider we are responsible according to § 7 Abs.1 TMG for own contents on these sides according to the general laws. According to §§ 8 to 10 TMG, however, we as a service provider are not obligated to monitor transmitted or stored third-party information or to investigate circumstances that indicate an illegal activity. Obligations to remove or block the use of information under general law remain unaffected. However, liability in this regard is only possible from the moment of knowledge of a specific infringement. Upon notification of appropriate violations, we will remove this content immediately.
Liability for content
Our offer contains links to external websites of third parties on whose contents we have no influence. Therefore we can not assume any liability for these external contents. The content of the linked pages is always the responsibility of the respective provider or operator of the pages. The linked pages were checked for possible legal violations at the time of linking. Illegal content was not recognizable at the time of linking. However, a permanent content control of the linked pages is not reasonable without concrete evidence of a violation of law. Upon notification of violations, we will remove such links immediately.
The content and works on these pages created by the site operators are subject to German copyright law. The duplication, processing, distribution and any kind of exploitation outside the limits of copyright require the written consent of the respective author or creator. Downloads and copies of this site are for private, non-commercial use only. As far as the contents on this side were not created by the operator, the copyrights of third parties are considered. In particular contents of third parties are marked as such. Should you still be aware of a copyright infringement, we ask for a note. Upon notification of violations, we will remove such content immediately.
The use of our website is usually possible without providing personal data. As far as on our sides personal data (for example name, address or eMail addresses) are raised, this takes place, as far as possible, always on a consentual basis. These data will not be disclosed to third parties without your explicit consent.
Please note that data transmission over the Internet (for example, when communicating by e-mail) may have security vulnerabilities. A complete protection of the data from access by third parties is not possible.
The use of our website is usually possible without providing personal data.As far as on our sides personal data (for example name, address or eMail addresses)are raised, this takes place, as far as possible, always on freiwilliger basis.These data will not be disclosed to third parties without your explicit consent.Please note that data transmission over the Internet (for example, when communicating by e-mail) may have security vulnerabilities. A complete protection of the data from access by third parties is not possible. The use of contact information published by third parties for the purpose of sending unsolicited advertising and information materials is hereby expressly excluded. The operators of the pages expressly reserve the right to take legal action in the event of unsolicited promotional information, such as spam e-mails.
Website imprint created by impressum-generator.de by Kanzlei Hasselbach