This blog provides comprehensive, objective solar power house information and resources for solar hot water panels, solar power electricity and solar home heating.

The distinctions between passive and active solar systems are explored in more depth on the solar hot water and solar home heating pages that follow.  Suffice it to say here that active systems are more complex and costly than passive systems, but passive solar has limitations on applications for which it is suitable.

The present status and future outlook of the solar power house is very bright.  Solar power is now economically viable for everyday use in the home for four reasons: improved technologies; economies of scale; do it yourself products; and various government incentives. 

Most homes in the industrialized part of the globe can currently utilize some forms of this sustainable and clean primary energy resource with adequate cost-benefits to justify installation.  So, solar power house installations provide a dual benefit to the user and community: lower power bills and a cleaner environment.

Also, solar heating technologies can be used in most any climate.  To take advantage of solar energy, all that is usually needed is to have an un-shaded area that faces either south, southeast or southwest.  The appropriate type of system to choose, including the type of collector and whether it is active or passive, depends on several factors.  These factors include your site, the climate you live in, installation considerations, cost, and how you would like your solar heating system to be used.

All solar water heater and solar space heater systems are comprised of some sort of solar collectors (panels), and all systems have some kind of storage device.  Active systems also have circulating pumps and controls; passive systems work without this added equipment.  Three types of solar collectors (panels) are used for home applications: flat-plate, integral collector-storage (ICS), and evacuated-Tube collectors.

By being properly informed and planning carefully you will be surer to choose the proper system for you and your family.  Learn and plan, and only then start installing systems as fast as your time, energy and funds permit.

One cost effective approach to learning while doing and stretching your money is a do-it-yourself (DIY) project.  And, the easiest and fastest pay-back DIY project is solar power hot water.  This is because conventional hot water heating is about 25% of your power bill, and an effective solar hot water installation can save up to about two thirds of this 25%.

Over the years I have reviewed many DIY alternative energy packages.  I have never experienced one more comprehensive and as simple to execute as the GreenDIYenergy package presented on the right of this page.  It is very modestly priced and it is truly designed and explained for the novice.  So, if you’re ready to get started doing while learning I encourage you to check this package out.

My name is Carter Reames; I am an engineer and first became involved in solar and other alternative energy activities  during the oil  embargo of 1973.  My solar interests were frustrated during the era of unreasonably cheap fossil energy.  But, with fossil fuel’s ever increasing costs and solar energy’s steadily decreasing costs, my passion for solar power has intensified.

The three major solar power house applications are solar hot water, solar home heating and solar power electricity.  Development of a solar power implementation strategy will of necessity require an examination and evaluation of numerous critical solar energy facts. 

Of first importance is an assessment of macro geographic and site specific factors, and current power usage quantities and local utility rates.  House orientation to the sun, shading of the site, area seasonal temperature ranges, and conventional utility cost are all examples of the critical factors that influence the feasibility of different solar power alternatives.  Also, if the house to be evaluated for solar already exists, this will most often limit the solar alternatives that are feasible. 

These considerations form the foundation of current costs, the potentialities of alternative solar applications, and the basis for calculating the cost-benefit for the alternative solar possibilities.  And of course, solar project financial and time availabilities and limitations must also be taken into consideration when developing a solar plan of action.

If all three of the major solar power house applications are feasible and one wanted to implement a staged plan in order of increasing cost and complexity, and in decreasing order of cost benefit; it will usually be solar hot water first.  The orders of the other two will more than likely be technology driven rather than cost or cost-benefit driven. 

If the type of heat is to be electric, the next solar application will of necessity be electricity.  If the type of solar heat is to be liquid or air based, then the decision can be made on a cost and cost-benefit basis.  However, it is important to determine what heating alternative is most likely to be used before installing a domestic hot water system.  If the solar home heating is to be liquid based, cost savings are possible by sizing some of the basic hot water infrastructure in order to accommodate the home heating application when it is added.

For a solar hot water system the fundamental decision is whether a passive or active system is to be built.  Subsequent decisions are refinements of this fundamental decision which are detailed in solar hot water panels. 

With solar home heating, there are three fundamental decisions: whether a water, air or electric heating system is to be used.  If the system is to be water or air, there are two subsequent fundamental decisions to be answered for this choice: whether to build a passive or active air or water system.  Additional details on these alternatives are in solar home heating.

There is also a fundamental decision to be made on a solar power electricity system that has significant cost ramifications. One possibility is to generate solar electricity and dump all excess electricity onto the electric grid and use the grid when the solar generation is insufficient for the house load (i.e., no storage). The other approach is to have a battery system to store excess solar generation for later use when house load exceeds the solar generation.   This subject is covered in greater detail at solar power electricity.        

Solar Hot Water 

The production of solar hot water is one of the most cost-effective solar power house applications; typically reducing conventional water heating cost by about two-thirds.  However, a solar heating system can save as much as 85% on hot water cost in some climates, which can be as much as 25% of total home energy costs.  All solar applications provide the dual benefit of reducing fossil power expenses and reducing the associated fossil fuel environmental impacts of conventional energy generation.  These are essential solar energy facts to understand for decision making.

The two main components of virtually all solar water-heating systems are solar panels which serve as the heat collectors, and a storage tank.   A fluid of some type (which is often water) is used to move the heat from the collector to its point of heat transfer, storage or usage.  The type of fluid and way it is handled will depend on how the hot water is used and the system employed to transport the fluid and transfer the heat.

There are two types of solar hot water systems; active and passive, but active systems are the most common.  The three main home uses of active solar hot water systems are to heat water for consumption, space heating, and heating swimming pools.  There are three types of solar panels (collectors) used in solar hot water systems, but the most common is the flat plate collector.

Active solar hot water systems

Active solar hot water systems use electric pumps, and controllers to circulate water (or other fluids) through the collectors. There are two categories of active solar hot water systems:

1. Direct-circulation systems which employ pumps to circulate pressurized potable water through the panels (the heat collectors). These systems are suitable only for areas that do not have extended periods of hard freezing.

2. Indirect-circulation systems pump a non-potable heat-transfer fluid through collectors. Heat exchangers transfer the heat from the fluid to the potable water. The two most common indirect systems are:

   • The antifreeze system which employs a heat transfer fluid that is usually a mixture water and a non-toxic food-grade propylene glycol.

   • The drainback system, which is a good choice in colder climates, pumps water through the collectors. The water in the collector drains back into a weather-protected reservoir tank when the pumps stop.

   

   

Passive solar hot water systems

Passive solar hot water systems use thermosyphon and gravity to naturally circulate water as it is heated.  Due to the absence of electrical components, passive systems require less maintenance, and have a longer useful life span. The two main types of passive systems are:

1. Integral collector storage systems: also known as ICS or “batch” systems, are good for areas that rarely experience freezing, in homes that have significant daytime and evening hot-water needs; but not predominantly morning needs.  They have one or more black storage tanks inside a glazed insulated box.  Cold water is first preheated in the solar collector tanks and then continues to a conventional water heater.

2. Thermosyphon systems: use the natural convection of warm water rising to circulate water from the tank through the collectors as water in the collector heats and rises naturally into the tank above.  To conceal it from view, the storage tank is often placed in the house’s attic of the solar power house. These systems are moderately priced, cost effective and reliable. Below is a skematic of a thermosyphon system:

Flat-plate solar hot water panels (collectors)

The solar power home hot water applications of consumption, space heating and pool heating only require temperatures at or below 180°F which is in the heating range of flat-plate panels.  Although evacuated-tube collectors can reach temperatures higher than 200°F, their cost is approximately double that of flat-plate panels. Therefore, flat-plat are almost exclusively used in these applications.

As depicted below,a flat-plate collector is typically an insulated box with a glass or transparent plastic cover and a black absorber plate.