The influence of uniform flow orifice on the effect of Naturally stratified Chilled water-storage tank
The widely use of cooled storage technology in our country will be an irreversible trend with the development and improvement of the TOU price policy. Naturally stratified Chilled water-storage is a very important cool storage technology. In this paper, the effect of using uniform flow orifice in naturally stratified water-storage with slotted pipe diffuser is studied by contrast experiments firstly. Then the cases with uniform flow orifice are simulated. Through the comparison of experimental data and simulation data, the correctness of the mathematical model is verified. Finally, the effect of water-storage is studied by simulation when the uniform flow orifice is set with different voltage drop. Conclusions can be obtained as follows: the layered effect is greatly improved by setting the uniform flow orifice; it is when the voltage drop of uniform flow orifice is in an appropriate range which is about ten to tens Pa that the improvement is obvious.
Constant flow rate charging characteristics of a full-scale stratified chilled water storage tank with double-ring slotted pipe diffusers.
Temperature distributions formed during charging of a 14 m (46 ft) water depth, 7 m (23 ft) radius stratified chilled water storage tank with double ring octagonal slotted pipe diffusers were recorded and analyzed. Prior to the beginning of each test, the tank was fully discharged and at a relatively uniform temperature. To the extent possible, inlet flow rate and temperature were held constant during each test. Six tests were performed for flow rates varying from 50% to 95% of design. Thermal performance was quantified using thermocline thickness, half-cycle figure of merit (FoM1/2) and equivalent lost tank height (ELH). The thermal performance for all tested charge flow rates was good by current standards (FoM1/2 > 90%, ELH < 1 m in all but one case). Thermocline thickness for low and medium flow rates was relatively small, on the order of 1 m (3 ft). Erroneously large thermocline thickness measurements were obtained in the high flow rate case because of the effect of inlet temperature variation combined with the definition used. Significant bulk temperature increase observed below the thermocline in all cases was most likely due to large-scale convection cells driven by the inlet flow. Efforts to improve the performance of diffusers should focus on suppressing this circulation.
Continuity, Legitimacy, and Agricultural Development: Conclusions
This chapter aims at bringing together the principal conclusions of the volume, emphasising some particular aspects and questions. Policy continuity in relation to the late 1980s was rightly defined by the Aylwin government policymakers as an essential instrument for further agricultural growth. But in a democratic environment the Aylwin policies, in part precisely because of their strong element of continuity, could be implemented only if they were perceived as legitimate by the majority of the rural population, and by the poor in particular. This means that substantial improvements in agricultural income distribution, and in the quantity and quality of the social services provided to the rural poor, were unavoidable. In order to achieve legitimacy it was, and is, necessary to introduce changes. A lucid, creative combination of continuity and change was the only guarantee of success for the Aylwin policies, and for those of future democratic administrations. Continuity and legitimacy are the fundamental pillars for democratic agricultural development.