Experimental Study on Match for Indoor and Outdoor Heat Exchanger of Residential Air-conditioner

In this study, the effects of indoor unit heat transfer area and air flow rate and outdoor unit air flow rate on the system performance of residential air-conditioner were experimentally investigated under rated cooling and heating conditions. The experimental results showed that the system cooling capacity, EER, heating capacity and COP all had evident variation with indoor unit heat transfer area and air flow rate and out unit air flow rate, which predicated that there was a proper match range for indoor unit and outdoor unit to make the system overall performance best. The increase of indoor unit heat transfer area and air flow rate significantly improved system cooling and heating performances especially for the smaller heat transfer area indoor unit, and the improvement was more obvious for heating performance. The heat transfer area ratio of indoor unit and outdoor unit was smaller, the indoor unit air flow rate should be designed as higher air velocity, but that should not be higher than 1.2m/s. In addition, with the specified outdoor unit in this study, the matched heat transfer area of indoor unit should not be too high or too low, and the optimal heat transfer area ratio of indoor and outdoor unit was between 0.33 and 0.37, which was better to choose the smaller value for higher indoor unit air flow rate. The increase of outdoor unit air flow rate also was advantageous for improving system cooling and heating performances especially for system EER and COP, but excessive higher air flow rate can cause the degradation of the system performance. The proposed outdoor unit designed air velocity should not be higher than 1.6m/s

A new error analysis for parabolic Dirichlet boundary control problems

In this paper, we consider the finite element approximation to a parabolic Dirichlet boundary control problem and establish new a priori error estimates. In the temporal semi-discretization we apply the DG(0) method for the state and the variational discretization for the control, and obtain the convergence rates $O(k^{\frac{1}{4}})$ and $O(k^{\frac{3}{4}-\varepsilon})$ $(\varepsilon>0)$ for the control for problems posed on polytopes with $y_0\in L^2(\Omega)$, $y_d\in L^2(I;L^2(\Omega))$ and smooth domains with $y_0\in H^{\frac{1}{2}}(\Omega)$, $y_d\in L^2(I;H^1(\Omega))\cap H^{\frac{1}{2}}(I;L^2(\Omega))$, respectively. In the fully discretization of the optimal control problem posed on polytopal domains, we apply the DG(0)-CG(1) method for the state and the variational discretization approach for the control, and derive the convergence order $O(k^{\frac{1}{4}} +h^{\frac{1}{2}})$, which improves the known results by removing the mesh size condition $k=O(h^2)$ between the space mesh size $h$ and the time step $k$. As a byproduct, we obtain a priori error estimate $O(h+k^{1\over 2})$ for the fully discretization of parabolic equations with inhomogeneous Dirichlet data posed on polytopes, which also improves the known error estimate by removing the above mesh size condition

Experimental Investigation of the Refrigerant Flow Distribution Characteristic of Heat Exchangers on the Residential Heat Pump Air Conditioner System Performance

In this study, the refrigerant flow distribution characteristic of fin-and-tube heat exchanger used as outdoor and indoor heat exchanger of a residential heat pump air-conditioner was experimentally studied and analyzed. The outdoor heat exchanger included “n shape†1 -circuit, 2-circuit and 3-circuit arrangements, and the indoor heat exchanger was only “n shape†2–ciucuit arrangement. It showed that the refrigerant flow distribution of both outdoor and indoor heat exchanger as evaporator would give much more system performance change of the residential heat pump air-conditioner than that as condenser. The refrigerant flow distribution characteristic can be expressed with the difference value of each circuit exit superheat as evaporator. The maximum difference value with little effect on system performance had been obtained both under cooling mode and heating mode. The maximum difference value was nearly the same at various test conditions and can be considered as 3℃. According to the experimental results, the system performance under heating mode especially for rated heating mode had more sensitive with refrigerant flow distribution characteristic than that under cooling mode, therefore the adjustment of refrigerant distribution characteristic of both the outdoor and indoor heat exchanger should mainly base on the rated heating mode

Study of R161 Refrigerant for Residential Air-conditioning Applications

In order to investigate the feasibility of R161 applied in residential air conditioner, the thermodynamic performance and comprehensive theoretical thermodynamic cycle of R161, R22 and R290 under various air-conditioner operating condition were carried out. Further more, the cooling and heating performance of R161 and R22 under various operating condition was investigated experimentally in a 3.5kW residential heat pump air conditioner. Property and thermodynamic cycle comparison showed that R161 has better thermodynamic performance than R290, the rated cooling and heating capacity is lower than R22 but higher than R290, the rated cooling and heating COP is higher than both R22 and R290. The experimental rated cooling capacity reduced 7.6% and rated cooling EER increased 6.1%, rated heating capacity reduced 6.8% and rated heating COP increased 4.7%, refrigerant optimized charge reduced 43% compared to R22 system, theoretical and experimental test revealed that R161 has lower discharge temperature than R22 system

Hemagglutinin sequence conservation guided stem immunogen design from influenza A H3 subtype

Seasonal epidemics caused by influenza A (H1 and H3 subtypes) and B viruses are a major global health threat. The traditional, trivalent influenza vaccines have limited efficacy because of rapid antigenic evolution of the circulating viruses. This antigenic variability mediates viral escape from the host immune responses, necessitating annual vaccine updates. Influenza vaccines elicit a protective antibody response, primarily targeting the viral surface glycoprotein hemagglutinin (HA). However, the predominant humoral response is against the hypervariable head domain of HA, thereby restricting the breadth of protection. In contrast, the conserved, subdominant stem domain of HA is a potential ‘universal’ vaccine candidate. We designed an HA stem-fragment immunogen from the 1968 pandemic H3N2 strain (A/Hong Kong/1/68) guided by a comprehensive H3 HA sequence conservation analysis. The biophysical properties of the designed immunogen were further improved by C-terminal fusion of a trimerization motif, ‘isoleucine-zipper’ or ‘foldon’. These immunogens elicited cross-reactive, antiviral antibodies and conferred partial protection against a lethal, homologous HK68 virus challenge in vivo. Furthermore, bacterial expression of these immunogens is economical and facilitates rapid scale-up

Expression of Bovine Interleukin-1β in a Bovine Herpesvirus-1 Vector:In VitroAnalysis

AbstractIn order to evaluate whether bovine herpesvirus-1 (BHV-1) could be used as a live viral vector for the expression of cytokines, we constructed a recombinant BHV-1 expressing bovine interleukin-1β (boIL-1β). The boIL-1β coding sequence, corresponding to the cleaved mature product, was fused with the BHV-1 glycoprotein C (gC) signal peptide sequence; the resultant gC-boIL-1β fusion gene was recombined into the gC locus of the BHV-1 genome. Southern blot analysis confirmed the proper genomic configuration of the recombinant virus. Results from transcript analysis showed that boIL-1β was expressed in infected cells with kinetics similar to that of gC. Indirect immunofluorescence and immunoprecipitation assays showed that the recombinant protein was produced in both cell-associated and secreted forms. Western blot analysis detected a 19.3-kDa protein. Further analysis, using an IL-1β bioassay demonstrated that both the cellular and secreted forms of recombinant boIL-1β possessed biological activity. The expression of the boIL-1β protein did not affect thein vitrogrowth efficiency of the virus, which exhibited similar growth kinetics to that of a simple gC deletion mutant. The results from this study demonstrate that BHV-1 can be used to express a functional cytokine, thereby establishing the basis to further study recombinant BHV-1 expressing cytokines as an alternative means to attenuate the virus and also as a potentialin situcytokine delivery system to modulate immune responses against BHV-1 and other cattle pathogens