To reduce CO${}_2$ emissions in the industrial sector, high-temperature heat pumps are a key technology. This work presents an approach to design such an industrial heat pump system capable of supplying 200 ${}^{°}$C sink temperature and a capacity of approximately 1 MW. Today’s market-available heat pumps using displacement compressors are not suitable for reaching that high sink temperatures as they need lubricating oil, which is not temperature resistant enough. As a consequence, in this study a transcritical heat pump cycle using a two-stage oil-free radial compressor is investigated. Based on preliminary studies, R1233zd(E) is chosen as a refrigerant. The procedure couples 1D thermodynamic cycle simulations with a radial compressor mean-line design model. A preliminary geometry for a compressor with and without inlet guide vanes is presented, and compressor maps including the compressors behaviour in off-design are calculated. The compressor design is then imported into a 1D simulation to analysis the performance of the heat pump in the whole operating range. In the analysis, the application of a fixed inlet is evaluated, and an improvement of approximately 21% and 16% of the isentropic efficiency is achieved. The thermodynamic simulations showed a maximum COP of approximately 2.8 and a possible operating range of 0.5 to 1.3 MW thermal power. Furthermore, a techno-economical analysis by means of a deep-fryer use case showed reasonable payback times of between 2 and 10 years, depending on the electricity to gas price ratio.

Background: Catheter ablation is a safe and effective treatment of ventricular arrhythmias (VAs). In this context, Remote Magnetic Navigation (RMN) has been shown to facilitate cardiac mapping and ablation of VAs.

Introduction: Catheter-based pulmonary vein isolation (PVI) is an established treatment option for atrial fibrillation (AF). Aim of this study was to quantify the extent of the ablation zone after wide area circumferential (WAC) PVI applying a novel high density mapping system (Rhythmia – Boston scientific). Methods: 20 consecutive pts underwent WAC-PVI for AF using the Rhythmia System in conjunction with the Orion mini-basket catheter, which was utilized to create a detailed 3-dimensional electroanatomic map of the LA and PVs during sinus rhythm, before and after the ablation procedure. Results: Mean pts age was 60 ± 4 years. 60 % had paroxysmal and 40% persistent AF. LA diameter was 45 ± 10 mm and LV ejection fraction was 55 ± 10%. PV anatomy was normal in all patients. A total of 9772 ± 3108 mapping points were taken for the initial map and 7910 ± 2344 points for the remap. Mapping time for the initial map was 19 ± 4.2 min and 10.8 ± 3.2 min for the remap. When comparing the initial voltage map with the remap after WAC – PVI, PVs and all PV antra, during remapping were isolated and displayed scar (<0.2mV), while the LA roof had scar in 10 out of 20 patients (50%), although intentionally no roof line was placed (Figure 1 showing left atrium voltage map performed before (A) and after ablation (B)). Posterior wall (PW) area during the initial map was 19,7 ± 3,5 cm2 and the ablated area at the PW during remapping was 7,8 ± 3,34 cm2 ( 40 ± 17%), although no additional lesions were intentionally placed. When the posterior wall was divided into four segments, there were no significant statistical differences regarding the location and extent of ablation zones at the PW after WAC-PVI (Table). Conclusion: Wide area circumferential PVI results in a high percentage of partial unintentional ablation of the LA posterior wall and roof, which can be visualized with high density mapping ablation. Clinical implications of these findings have to be elucidated in future studies.

Background: Several algorithms have been proposed to distinguish the origin of focal atrial tachycardia from the PVs. The presence of "M wave" pattern in precordial leads has been considered as a marker of left PV atrial tachycardia.