Kim Holland Tube

Recently I was talking of different types of solar panels for hot water with the owner of a business considering the purchase of a system. I had heard many evacuated Kim Holland tube collectors, but I knew that the system that was in him offering using flat plate collectors. ("Collectors" are simply another name for panels because they collect solar energy). He then asked me what type of Panel has been better. "The answer is simple," he said. "Both". It is obviously not quite cut and dried. The answer is by drawing the curve of the slope against the point of intersection of the two types of sensors in the same graph. This graph shows that the flat plate collectors are about 80% effective when the water temperature is equal to the temperature of the outside air (atmosphere). The increase in the difference in temperature between the air and water, the efficiency of a flat plate collector falls. Evacuated tube collectors are only 50% efficiency when air and water temperatures are equal. But its effectiveness is falling step so quickly at high temperatures. In the same graph, the two curves (crossing point) cross each other around the brand differential 140oF. By then, before the transition (to the left of the graph), flat plate collectors are more effective. To the right of the ramp, evacuated tube collectors are more effective. For example, say that 40oF is degrees outside. A collector's plate will be more effective if and when the water temperature is lower than 180oF. An evacuated tube collector will be more efficient that the water temperature rises above 180oF. In the days when the outside temperature is 0oF, the crossing point of efficiency occurs when the water temperature 140oF. Usually, hot domestic (EDC) and applications of heating (HS) occur before the crossing. For applications of high temperature, such as absorption chillers, vacuum tube collector work best. From tubes of vacuum are generally more expensive than flat plates on a basis per square foot of costs, you can go beyond the point of junction of ways a little and be even better with flat plate collectors. There is no valid reason, I believe that use tube collectors in residential applications. There is a long list of business applications that are better served by flat screens. Therefore, when choosing between the tube and plate flat solar hot water panels, the most critical factor is the temperature that will work for a given application.