Lägesrapporter

Kvartal 2, 2010

• The paper called "Experimental Analysis Of A Variable Capacity Heat Pump System- Focusing on the compressor and inverter loss behavior" was presented (oral presentation) in the 20th International Compressor Engineering Conference at Purdue, USA.

• The paper called "Retrofitting a variable capacity heat pump to the ventilation heat recovery systems: modeling and performance analysis" was accpeted to be published in International journal of appiled energy.

• The paper called "The Ground Source Heat Pump: A System Analysis With A Particular Focus on The U-pipe Borehole Heat exchanger" was presented (poster presentation) in the International Heat Transfer conference at Washington DC, USA.

•Measurments were done on the variable speed heat pump test rig located in KTH's lab. The focus of the measurments were on evaluating the effect of the inverter switching frequency on the compressor and inverter losses. furthermore, several tests were conducted to evaluate the effect of changing the compressor frequency and secondary fluid mass flow rate on the heat transfer coefficients of both condenser and evaporator.

•The efforts have been made to develop the available models, specially the evaporator, condenser, and borehole models, in order to make them more advanced and more detailed.

• Individual project meetings were held with some of the project sponsors. For example, a project meeting with Wilo in Växjö, with Thermia in KTH, with ETM Kylteknik in KTH, etc.

Kvartal 1, 2010

• Several siumlationS and modeling have been done based on the demands from Thermia, NIBE, CTC Enertech, etc. Detailed modeling of several heat pump units have been done and annual modeling of several heat pump systems with different system characteristics and at different operating conditions have been carried out. The results have been discussed with the companies and the process is still going on.

• Two journal papers called "Capacity control in ground source heat pump systems Part I:modeling and simulation" and "Retrofitting a variable capacity heat pump to a ventilation heat recovery system: modelling and performance analysis" were submitted to International Journal of Refrigeration.

•Measurments were done on the variable speed heat pump test rig located in our lab. The focus of the measurments were on the inverter and compressor losses when the compressor speed changes. the measurments were done for the system with two different refrigerants, R134a and R407c. the results were published in a paper called "Experimental Analysis Of A Variable Capacity Heat Pump System- Focusing on the compressor and inverter loss behavior". the paper were submiteed to the 20th International Compressor Engineering Conference at Purdue.

• Individual project meeting were held with the project sponsors mostlt at their places. meeting with NIBE at Markaryd, Thermia at Arvika, Climacheck at Stockholm, CTC Enertech and ETM Kylteknik at kth are examples of these meetings,

Kvartal 4, 2009

• Two papers called "Retrofitting a variable capacity heat pump to a ventilation heat recovery system: modleing and performance" were sumbitted to the International Conference on Applied Energy (ICAE 2010). Both papers were accepted and they will be published in the conference proceediing.

• A paper called "The ground source heat pump: a system analysis with a particular focus on the U-pipe borehole heat exchanger" was submitted to the ASME (American Society of Mechanical Engineers) Heat Transfer Conference. In cooperation with Effsys P8.

• In-situe field measurment has been done during the heating season for a heat pump system equipped with both variable speed compressor and pump (the borehole pump).

• The project was presented both orally and by poster in the EFFSYS2 day, held in KTH Decmber 14th.

• Individual project meeting were held with the project sponsors as usual. Several meetings (including phone meetings) with Thermia, CTC Enertech, and ETM Kylteknik are some examples of these meetings. Furthermore,internal meetings have been held regularly with the project team.

Kvartal 3, 2009

• Two papers called "Ventilation heat recovery with run around coil: System analysis and a study on efficiency improvement – Part I and part II" were presented in the ASHRAE (American Society of Heating, Refrigeration, and Airconditionig) Chapters Regional Conference.

• The model of heat pump system including buildling, ground heat source, climate, heat pump unit, storage tank, etc. was modified and have been run for many different conditions. Due to the significant size of the model, running the model over a year takes about one day that makes the data processing very slow.

• The journal papers were modified based on the last changes in the model components.

Kvartal 2, 2009

• A test rig has been made in the laboratory of division of thermodynamics and Refrigeration, KTH. The rig aims at testing the heat pump system at different compressor and pumps speeds, and also evaluating the inverter and compressor losses in details.

• The paper called "Variable-capacity ground-source heat pump systems in single-family houses: Dynamic modelling and simulation- Part I" was modified and it is ready to submit to the International Journal of Refrigeration.

• Two papers called "Ventilation heat recovery with run around coil: System analysis and a study on efficiency improvement – Part I and part II" were witten and submitted to the ASHRAE (American Society of Heating, Refrigeration, and Airconditionig) Chapters Regional Conference. Both papers were peer reviewed and accepted and they are going to be presented in the conference on October.

• Heat pump system modelling for some special cases has been done based on the requests from the companies. The modelling includes both on/off controlled and variable speed heat pump systems.

• The models for some of the components in the heat pump system such as evaporator and condenser have been developed. storage tank model is also added to the system.

• Individual project meeting were held with the project sponsors as usual. For example, A meeting with Thermia in Arvika, with CTC Enertech in KTH, and several meetings with Climacheck and ETM Kylteknik in KTH are some examples of these meetings. The project was also presented in the effsys board meeting.

Kvartal 1, 2009

• A draft version of a journal paper called "Variable-capacity ground-source heat pump systems in single-family houses: Dynamic modelling and simulation- Part I" was written and submitted. The paper, now, is under the process of review and modification.

•The heat pump unit model which was already made has been developed and modified. then the results of the modelling were compared with the experimental data and the model showed higher accuracy in comparison with the results from the old model.

•Thermia's heat pump units (Diplomat 6 and Diplomat 16) have been modelled as following:

1. the losses in the compressors of these units were modelled in details. By this model, the characteristic parameters which represent the compressor losses in these units were found. So, at every operating point, it is possible to predict how much the power input to the compressor is and how the losses are changing based on change in the operating conditions.

2. the units (Diplomat 6 and 16) were modelled. So by this models, it is possible to find out how these units behave by changing the mass flow rate in the brine in the evaporator side (in a case of variable speed pump in the borehole), changing the heating water in the condenser side, or changing the compressor frequency (in the case of adding an inverter and having a variable speed compressor).

3.The diplomat 6 and diplomat 16 were put in a 120 m2 and 300 m2 single family houses, Respectively. Then, they were modelled over a year with one hour time step. The houses have typical building materials and typical user behaviours and they were located in Stockholm. The results shows COP, compressor power, the supply temperature to the building, etc at every single hour over a year.

By this models, it is also feasible to do the annual modelling for any house in any place in the world, with different user behaviors, at different time periods in a year and with different temperature levels of the heating systems (floor heating or radiator systems). The modelling can aslo be carried out with a shorter time steps.

•The initial negotiations and planning have been done for building a heat pump test rig in KTH in order to test the losses behavior of at least two different variable speed compressor. the study will also cover different types of frequency converters and motors (together) and their losses in the system.

•The field measurements have been continiously done during the cold months, mainly by the help of ETM Kylteknik (Kenneth Weber) and Climacheck.

•A short paper was written and is going to be submitted to REHVA journal (the journal of Federation of European Heating and Air-conditioning Associations). The paper mainly presents the project and describes the main aims and methodology for this project, as one of Effsys2 projects.

•Two paper abstracts have been sent to the ASHRAE Chapters Regional Conference which is going to be held in October. The papers are called "Ventilation heat recovery with run around coil: System analysis and a study on efficiency improvement – Part I and part II".

Kvartal 4, 2008

• Having some of the project participants such as NIBE (located in Markaryd), CTC (located Ljungby), Thermia (located in Arvika) and also having several meetings with Climacheck and ETM Kylteknik in Stockholm. During these meetings, some example of modelling results were shown and discussed. Then, the companies main requirements and interests were clarified and discussed. Every company had its own interest in moddeling a specific case; so all the models made so far including building, heat source (ground or outside air), climate, and heat pump unit model will serve the special interest of every company.

•The well-known pump manufacturer and company called Wilo was visited (it is located in Växjö). The project, its methodology and the results so far were presented to the cpmanys' representatives. Then Wilo accpeted to become one of the official sponsors of the project and provide the required outsources. Consequently, a Wilo stratos pump as a high efficiency variable speed pump was provided by Wilo and installed in one of the fields under measurement in Stockholm.

•Another variable speed heat pump system installed in a single family house in Stockholm was equipped with the required measurement equipments and appartus supplied by Climacheck (one of the project sponsors); so all of its important parameters is monitored online during the heating season.

•Heat pump system modelling for some special cases has been done based on the requests from the companies. The modelling inludes both on/off controlled and variable speed heat pump systems. The results will be sent to them very soon.

•The field measurements have been done and the outputs have been analyzed extensively. The analysis is used for validation of the models and also to understand the system behavior under different operating conditions. For example, in a system with both variable speed pump and compressor, the speed of the pump in the ground source side (the boreholes) was changed in a wide range in order to see how the compressor speed reacts specifically and how the system is influenced generally.

Kvartal 3, 2008

•Development of a control algorythm for a residential heat pump system which is able to find the optimum speed of compressor and ground source pump at every operating point. A bottom-up approach is used for the system modeling i.e. the components of a heat pump system including compressor, evaporator, condenser, building, climate, ground source, etc. are modelled individually; then all the individual models are linked together to form the top-level system.

• Holding the annual project seminar in KTH in the presence of most of the project sponsors such as Thermia, NIBE, CTC, ETM Kylteknik, etc. During the seminar, a litertaure survey report called "capacity control in heat pump system:methods and strategies" was submitted to all the participants. Furthermore, the project was presented and discussed in three different parts:
1.Modeling and simulation
2.Experiments
3.Future plans

During the meeting, a lot of feedbacks were recieved from the companies' representatives about what has been done so far and what can be done in the future. At the end, the decision was made to visit all the project sponsors up to end of the year and discuss the modeling and experimental issues individually and in more details.

•Preparation for several field measurments in the coming heating season. The field measurments includes both variable speed and on/off controlled compressors, different building sizes (single family houses), different refrigerants (R134a and R407C), and different types of compressors (scroll, reciprocating and rotary compressors).

•Making arrangements for installing the variable speed pump in some of our test fields. The primary negotiations were made with some of the renowned pump manufactureres such as Wilo and Grundfus. so by the help of the possible new project participants, it will be possible to try the recently-developed control algorythms on the field and validate the models based on that.

EFFSYS2 dagen 2008-11-11 presentationsmaterial poster

Kvartal 2, 2008

The activities done during Apr-June.2008:
•Continuation of EES/TRNSYS modeling of a heat pump system including the detailed model of building, variable speed heat pump unit, and ground source. The detaild heat pump unit model made at this stage is able to find the optimum frequency for the compressor according to the demand, the source temperature going to the evaporator, and the load temperature going to the condenser. A borehole model was also made based on the experiments being done in another research project.
• Making the performance data for a variable speed ground-source heat pump system based on an EES modeling. By these system performance data, if the source and load temperature, and the frequency are given at each time step, the heating capacity, the compressor work, and consequently the system COP can be achieved. The performance data table are called from TRNSYS in order to make the system analysis. For example, the seasonal performance factor of the system can be analyzed in different system temperature level (eg. 55/45 or 45/35), with or without considering the role of building inhabitant behavior, applying different sizes of building, and also different range of compressor frequencies.
•Poster presentation and participation in the IEA heat pump conference in Zurich
•Participation in EES/TRNSYS days in Thermodynamis laboratory, University of Liege, Belgium
•Several meetings with some of the project sponsors such as NIBE, Thermia, and ETM Kylteknik
•Primary negotiation to have new project sponsors

Kvartal 1, 2008

•Development of the heat pump unit model in EES and model validation according to the experiment results. Several models have been built and the accuracy of them have been analyzed and compared. The main focus of the models was on the compressor losses, superheat temperature provided by TXV and EEV, and condensation and evaporation temperature changes based on changes in refrigerant mass flow rate, heat exchangers' UA values, and both source and sink side temperatures.
•Writing the paper called "Variable capacity heat pump system, modelling and simulation" for IEA Heat pump conference. Two journal papers called "variable speed heat pump systems in transient condition" and "Capacity control of heat pump systems: a comprehensive litertaure review" have also been started.
• Data processing due to the experiments done on variable speed heat pump system with rotary compressor and electronic expansion valve (installed in three different locations)
•Data processing and system optimization of a variable speed heat pump system with scroll compressor and thermostatic expansion valve installed in Stockholm
•Several meetings with some of the project sponsors such as ETM Kylteknik, Climacheck, and CTC. The meeting with some other sponsors such as Thermia, NIBE, and ILK Dresden have also been scheduled.

Kvartal 4, 2007

• Development of heat pump system model based on different building specifications and different heating distribution system (both radiator and floor heating system). TRNSYS and EES are used as the computer tools (co-solving).
• Development of detailed heat pump unit model in EES. At this stage, the parameter estimation model which had been made before was developed for both single speed and variable speed and also both scroll and reciprocating compressor cases. Then the heat pump unit model for both variable speed and single speed cases has been fed by the available test data in order to get results and also to validate the model.
• Processing the experiment data which have been recieved from some of the project partners (4 Variable speed cases and two single speed cases.
• Visiting some of the project sponsors such as NIBE (Markaryd), CTC (Ljungby), and Copeland (Belgium) and also having a few meetings with Kenneth Weber (from ETM Kylteknik) and Rolf Christensen (AlfaLaval) in order to inform them about the activities done so far, get the available test data from them, and make the future steps as close as possible to their expectations.Some other companies will be vistited very soon.
• Preparation for holding a seminar on electrical aspects of the project with some experts in this field during the coming spring. Accoring to that, Jan-Erik Nowacki (KTH) and Mats Leksell (Electrical department of KTH) were met and some initial agreements were made between the Electrical and Energy technology departments of KTH.

Kvartal 3, 2007

Kontakter har tagits med deltagande företag och besök hos de stora värmepumptillverkarna har genomförts.

Inventering av befintliga lämpliga modeller för värmepumpar, för berggrunden och för byggnader har genomförts.

The activities done during July-Sep.2007:
• Making the first system’s model including a heat pump unit as a black box, building, climate, heat source, and control units and etc. EES and TRNSYS have been used as the simulation tools.
• Making the second system’s model in EES based on the detailed parameter estimation model of the heat pump unit.
• Development of the parameter estimation model for a variable speed compressor heat pump unit.
• Development of the building model used in the heat pump system based on the multi-zone building model in TRNBUILD
• Doing a comprehensive literature survey in order to collect and understand all the research projects done so far around the world. The focus of literature survey at this stage was on:
1. Control strategies and capacity control applied in heat pump systems.
2. Variable speed compressor heat pump units
• Having individual and group meetings with the project participants.

EFFSYS2 dagen 2007-11-08 presentationsmaterial

Kvartal 2, 2007

Literature study
As the first step and one of the most important parts of any project, a comprehensive literature study has been done. On this way, about 70 journal papers, conference proceedings, and books related to the project subject have been found. Many of them have been studied so far in order to find what was already done in this field around the world
Preliminary Modelling
As the first step of modelling, the system objectives and boundary (Churchman approach) were well defined. Then the conceptual model including all the components and their interconnections was built and the flow diagram of our preliminary model was made.

For the computer modelling of the project, TRNSYS and EES have been selected as our tools. The preliminary heat pump model was made in EES environment. This EES model is able to make the performance matrixes and to interpolate in two dimensions in order to find COP1 and Q1 based on the received load and source side temperatures.

Furthermore, it has been tried to make TRNSYS/EES coupling in order to exchange the data among the climate, building, control, heat source and heat pump models in an appropriate way.

In order to develop our heat pump model in EES, it has been tried to reconstruct the newest and most advanced available heat pump model in the world. So the parameter estimation model made by Jin&Spitler (2002) was selected as the initial pattern and it is tried to develop our EES heat pump model based on it.
Meeting with most of the project sponsors in Sweden
In order to find the major expectations of the sponsors from this project, several meeting were held with some of the project sponsors in Sweden. We have several meetings with Holger Svensson and Ted Holmberg from NIBE, Klas Berglöf from Climacheck, Martin Forsen from SVEP, and Kenneth Weber. During these meetings, the project participants gave their comments and expectations from the project. It was also agreed with them to have regular meeting every two or three months and also have a workshop in KTH during fall 2007 in which all the project sponsors will participate.
Sending the abstract to IEA heat pump conference
The 9th international heat pump conference which is the most important one in Europe will be held in Zurich, May 2008. So an abstract of the paper called “Dynamic simulation of capacity-controlled ground-source heat pump systems – preliminary results” was sent and accepted for inclusion in the conference.

Kvartal 4, 2006 och Kvartal 1, 2007

Genast efter beslut startades rekrytering av doktoranden till projektet. (Annons var införd i DN i mitten av december och sista ansökningsdag var i början av januari. De flesta intervjuer utfördes under januari. Dock var urvalet inte slutgiltigt klart förrän flera veckor senare. Den utvalde doktoranden heter Hatef Madani. Han avslutar under våren sina studier på KTH och kan därför inte påbörja sin anställning tidigare än i mitten av maj.
Ett noggrant arbete lades på urvalet av doktoranden då vi av erfarenhet vet att valet är mycket viktigt för projektets framgång.

Kontakter har tagits med deltagande företag och besök hos de stora värmepumptillverkarna har förberetts.

Inventering av befintliga lämpliga modeller för värmepumpar, för berggrunden och för byggnader har genomförts.