Dynamic whole system testing of combined renewable heating systems : the current state of the art

Objective: For the evaluation of the energetic performance of combined renewable heating systems that supply space heat and domestic hot water for single family houses, dynamic behaviour, component interactions, and control of the system play a crucial role and should be included in test methods. Methods: New dynamic whole system test methods were developed based on “hardware in the loop” concepts. Three similar approaches are described and their differences are discussed. The methods were applied for testing solar thermal systems in combination with fossil fuel boilers (heating oil and natural gas), biomass boilers, and/or heat pumps. Results: All three methods were able to show the performance of combined heating systems under transient operating conditions. The methods often detected unexpected behaviour of the tested system that cannot be detected based on steady state performance tests that are usually applied to single components. Conclusion: Further work will be needed to harmonize the different test methods in order to reach comparable results between the different laboratories. Practice implications: A harmonized approach for whole system tests may lead to new test standards and improve the accuracy of performance prediction as well as reduce the need for field tests.

Testing of combined heating systems for small houses: Improved procedures for whole system test methods : Deliverable 2.3

Dynamic system test methods for heating systems were developed and applied by the institutes SERC and SP from Sweden, INES from France and SPF from Switzerland already before the MacSheep project started. These test methods followed the same principle: a complete heating system – including heat generators, storage, control etc., is installed on the test rig; the test rig software and hardware simulates and emulates the heat load for space heating and domestic hot water of a single family house, while the unit under test has to act autonomously to cover the heat demand during a representative test cycle. Within the work package 2 of the MacSheep project these similar – but different – test methods were harmonized and improved. The work undertaken includes:  • Harmonization of the physical boundaries of the unit under test. • Harmonization of the boundary conditions of climate and load. • Definition of an approach to reach identical space heat load in combination with an autonomous control of the space heat distribution by the unit under test. • Derivation and validation of new six day and a twelve day test profiles for direct extrapolation of test results.   The new harmonized test method combines the advantages of the different methods that existed before the MacSheep project. The new method is a benchmark test, which means that the load for space heating and domestic hot water preparation will be identical for all tested systems, and that the result is representative for the performance of the system over a whole year. Thus, no modelling and simulation of the tested system is needed in order to obtain the benchmark results for a yearly cycle. The method is thus also applicable to products for which simulation models are not available yet. Some of the advantages of the new whole system test method and performance rating compared to the testing and energy rating of single components are:  • Interaction between the different components of a heating system, e.g. storage, solar collector circuit, heat pump, control, etc. are included and evaluated in this test. • Dynamic effects are included and influence the result just as they influence the annual performance in the field. • Heat losses are influencing the results in a more realistic way, since they are evaluated under "real installed" and representative part-load conditions rather than under single component steady state conditions.   The described method is also suited for the development process of new systems, where it replaces time-consuming and costly field testing with the advantage of a higher accuracy of the measured data (compared to the typically used measurement equipment in field tests) and identical, thus comparable boundary conditions. Thus, the method can be used for system optimization in the test bench under realistic operative conditions, i.e. under relevant operating environment in the lab.   This report describes the physical boundaries of the tested systems, as well as the test procedures and the requirements for both the unit under test and the test facility. The new six day and twelve day test profiles are also described as are the validation results.

Den goda viljan och framtida lönsamhet : En studie om nedskrivning av goodwill är en ledande indikator på framtida minskad lönsamhet i svenska och finska börsnoterade bolag

Bakgrund: Goodwill är en omdebatterad immateriell tillgångspost. En nedskrivning ska enligt redovisningsstandarden IAS 36 baseras på bolagens framtida ekonomiska utveckling. Därmed kan en nedskrivning vara en indikation på hur bolagets ekonomiska framtid kommer att gestalta sig. Tidigare forskning visar att bolagsledningens subjektiva bedömningar kan leda till att nedskrivningens relevans kan ifrågasättas. Syfte: Enligt IFRS 3 och IAS 36 ska goodwill värderas till det framtida uppskattade värde som tillgången ska generera. Grundtanken med standarderna är att öka tillförlitligheten och relevansen för att bättre återspegla bolagens ekonomi i de finansiella rapporterna. Utifrån grundtanken bör en nedskrivning av goodwill vara en ledande indikator på framtida minskad lönsamhet. Vi avser därmed att undersöka om det finns ett samband mellan nedskrivning av goodwill och minskad framtida lönsamhet i svenska och finska börsnoterade bolag samt om det finns en skillnad mellan länderna när det gäller sambandet. Metod: Uppsatsen är baserad på en kvantitativ metod med en deduktiv ansats där sekundärdata hämtats från databas samt årsredovisningar. Informationen har samlats in för att därefter testas med regressionsanalyser. Slutsats: Studien kan inte styrka att standarden ger en bättre återspegling av bolagens ekonomi i de finansiella rapporterna. Resultatet visar att hanteringen av goodwill kan ske utifrån ett opportunistiskt beteende då nedskrivningen kan vara baserad på en redan realiserad försämring av goodwill istället för att vara baserad på framtida bedömningar. Resultatet antyder att tillsynen inte är harmoniserad inom EU, då det finns en signifikant skillnad mellan Sverige och Finland två år efter nedskrivningen. Studiens resultat kan användas till att ifrågasätta gällande standardens utformning.