Demonstration of a small‐scale power generator using supercritical CO_(2)

The supercritical CO_(2)(sCO_(2))power cycle could improve efficiencies for a wide range of thermal power plants.The sCO_(2)turbine generator plays an important role in the sCO_(2)power cycle by directly converting thermal energy into mechanical work and electric power.The operation of the generator encounters challenges,including high temperature,high pressure,high rotational speed,and other engineering problems,such as leakage.Experimental studies of sCO_(2)turbines are insufficient because of the significant difficulties in turbine manufacturing and system construction.Unlike most experimental investigations that primarily focus on 100 kW‐or MW‐scale power generation systems,we consider,for the first time,a small‐scale power generator using sCO_(2).A partial admission axial turbine was designed and manufactured with a rated rotational speed of 40,000 rpm,and a CO_(2)transcritical power cycle test loop was constructed to validate the performance of our manufactured generator.A resistant gas was proposed in the constructed turbine expander to solve the leakage issue.Both dynamic and steady performances were investigated.The results indicated that a peak electric power of 11.55 kW was achieved at 29,369 rpm.The maximum total efficiency of the turbo‐generator was 58.98%,which was affected by both the turbine rotational speed and pressure ratio,according to the proposed performance map.

The simulation and mapping of building performance indicators based on European weather stations

Due to the climate change debate, a lot of research and maps of external climate parameters are availtabte. However, maps of indoor climate performance parameters are still Lacking. This paper presents a methodology for obtaining maps of performances of similar buitdings that are virtually spread over whole Europe. The produced maps are useful for anaty-zing regional climate influence on building performance indicators such as energy use and indoor climate. This is shown using the Bestest building as a reference benchmark. An important application of the mapping tool is the visualization of potential building measures over the EU. Also the performances of singte building components can be simulated and mapped. It is concluded that the presented method is efficient as it takes less than 15min to simulate and produce the maps on a 2.6GHz/4GB computer. Moreover, the approach is applicable for any type of building.

How does map use differ in virtual reality and desktop-based environments?

Maps based on virtual reality(VR)are evolving and are being increasingly used in the field of geography.However,the advantages of VR based on the map use processes of users over desktop-based environments(DEs)are not fully understood.In this study,an experiment was conducted in which 120 participants performed map use tasks using maps and globes in VR and DE.The participants’eye movements and questionnaires were collected to compare the map use performance differences.We analyzed the general metrics,information searching and processing metrics of participants(e.g.response time,RT;average fixation duration,AFD;average saccade duration,ASD;saccade frequency,SF,etc.)using maps and globes in different environments.We found that the participants using VR processed information more efficiently(AFDDE=233.34 ms,AFDVR=173.09 ms),and the participants using DE had both a significantly shorter response time(RT_(DE)=88.68 s,RT_(VR)=124.05 s)and a shorter visual search time(ASD_(DE)=60.78 ms,ASD_(VR)=112.13 ms;SF_(DE)=6.30,SF_(VR)=2.07).We also found similarities in accuracy,satisfaction and readability.These results are helpful for designing VR maps that can adapt to human cognition and reflect the advantages of VR.