Prediction of Fin Efficiency, Air Side Heat Transfer Coefficient, and Air Side Pressure Drop of Flat Tube Heat Exchanger

Heat exchangers equipped with circular tubes are generally used in air conditioners. Recently, air conditioners using heat exchangers equipped with flat tubes for higher performance have been enlarging. It is also effective for increasing the efficiency of the air conditioner to improve the performance by optimal design of the heat exchanger. Therefore, it is important to improve the accuracy of the air side performance prediction method. In this study, we propose a new method to predict air side heat transfer characteristics and air side pressure drop characteristics of the flat tube heat exchanger using the numerical analysis. The calculation results, using a new fin efficiency equation with corrections in the row pitch direction and the column pitch direction, agree well with the numerical analysis results taking into account the air side local heat transfer coefficient. In addition, the calculation results, using non-dimensional equations for the air side heat transfer coefficient and the air side pressure drop under dry conditions in conventional form, and a new fin efficiency equation, agree well with the numerical analysis results and the measurement results. Furthermore, in wet conditions, it is suggested that the existence of the slit has a significant effect on the water film thickness around the pipe backcalculated from the measurement results and the non-dimensional equation

Does the Use of Nursing-Care Services Reduce the Information about Dementia Patients Provided by Their Caregivers?

Background: The rate of use of nursing-care services has been increasing dramatically in recent years with the upgrading of the public long-term care insurance system in Japan. We addressed how the increased use of the nursing-care services might affect the information on the patients provided by their caregivers. Methods: A questionnaire survey of 531 family caregivers caring for dementia patients at home was carried out to investigate how the use of these services might affect the information about the patients provided by the caregivers. The survey revealed that the use of the nursing-care services reduced the burden (quality, quantity, time of nursing care, and feeling) on the caregivers. Results: According to the observation provided by the caregivers, the patients’ behaviors and activities at home tended to decrease. These results indicated that the use of the nursing-care services resulted in a reduction in the opportunity for and the time spent on observation of the patients by the caregivers, making it more difficult for the caregiver to provide an appropriate assessment of the patient’s condition. Conclusions: We discussed the impact of the use of the nursing-care services on the Clinician’s Interview-Based Impression of Change plus (CIBIC-plus) rating. Due to the reduction in the time spent on nursing care and in the opportunity for observation of the patient’s activities of daily living by the caregiver resulting from the use of the nursing-care services, it is difficult to obtain an accurate picture of the patient’s clinical condition using the CIBIC-plus, probably leading to an inappropriate CIBIC-plus rating