Author: workhouse123
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Passive space-heating design
Passive solar heating systems require little, if any, non-renewable energy to function. Every building is passive in the sense that the sun tends to warm it during the day and it loses heat at night. Passive systems incorporate the solar energy collection, storage, and distribution into the architectural design of the building and make minimal…
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Thermal load estimation
When estimating the building thermal load, adequate results can be obtained by calculating heat losses and gains based on a steady-state heat transfer analysis. For more accurate results and for energy analysis, however, transient analysis must be employed, since the heat gain into a conditioned space varies greatly with time, primarily because of the strong…
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Practical considerations
Installation of large collector arrays presents specific piping problems. This section examines issues related to the installation of pipes, supports, and insulation; pumps; valves; and instrumentation. Generally, the plumbing involved in solar energy systems is conventional, except in cases where a toxic or non-potable heat transfer fluid is circulated in the collector loop. A general…
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Simple system models
The equations presented in this chapter can be combined and used to model the whole system. The model includes all physical components of the system, such as the collector, storage tank, heat exchanger, loads, and heat losses from the system components, such as pipes and storage tank. Detailed models result in a set of coupled algebraic…
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Solar water heater performance evaluation
Many test procedures have been proposed by various organizations to determine the thermal performance of solar water heaters. Testing of the complete system may serve a number of purposes. The main one is the prediction of the system’s long-term thermal performance. System testing may also be used as a diagnostic tool to identify failure and…
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Hot water demand
The most important parameter that needs to be considered in the design of a water-heating system is the hot water demand over a certain period of time (hourly, daily, or monthly). The energy demand, D, required for the generation of sanitary hot water can be obtained if the volumetric consumption, V, is known for the required time…
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Differential temperature controller
One of the most important components of an active solar energy system is the temperature controller because a faulty control is usually the cause of poor system performance. In general, control systems should be as simple as possible and should use reliable controllers, which are available nowadays. One of the critical parameters that need to be…
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Module and array design
Module design Most commercial and industrial systems require a large number of collectors to satisfy the heating demand. Connecting the collectors with just one set of manifolds makes it difficult to ensure drainability and low pressure drop. It would also be difficult to balance the flow so as to have the same flow rate through all…
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Heat storage systems
Thermal storage is one of the main parts of a solar heating, cooling, and power generating system. Because for approximately half the year any location is in darkness, heat storage is necessary if the solar system must operate continuously. For some applications, such as swimming-pool heating, daytime-air heating, and irrigation pumping, intermittent operation is acceptable,…
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Active systems
In active systems, water or a heat transfer fluid is pumped through the collectors. These are usually more expensive and a little less efficient than passive systems, particularly if antifreeze measures are required. Additionally, active systems are more difficult to retrofit in houses, especially where there is no basement, because a space is required for…