Summary

The heating, ventilation and air-conditioning systems are a blend of loosely coupled systems to provide maximum energy efficiency and redundancy.

Design Considerations

AAmpere (amp), SI unit of electrical current basic heating, ventilation and air conditioning system is described below. In this case the design goal is a year-round live-aboard in north-eastern North America. For completeness in understanding the trade-offs made, the engine cooling system, hot water and refrigeration and watermaker are also shown. Some of the design considerations are:

   * One single fuel type on board
   * Minimize ACAlternating current loads
   * Minimize sound transmission
   * Pre-heat water for the water maker
   * Minimize energy usage
   * Maximize efficiency
   * Minimize dependencies
   * Provide redundancy

The requirement for a single fuel type effectively eliminates propane heating in favour of diesel. Diesel is anyway much safer. It is also more efficient, providing around 140,000 BTUBritish Thermal Unit (British Thermal Units) per gallon, compared to 91,000 for propane.

Distribution

The first major issue is whether to use forced air or circulating water to distribute heating and cooling. In the beginning, memories of cold radiators in grade school in the dead of a Canadian winter, and the comfort of humidity control with forced air in modern homes predisposed me to forced air. Over time, I changed my mind several times. In the end, circulating water was chosen to:

   * Reduce the size of ducts in the insulated space
   * Eliminate a path for airborne noise and dirt from the engine room
   * Reduce the general level of air-borne dust
   * Eliminate the need for a cold-air return
   * Minimise openings in watertight bulkheads
   * Deliver a more even heat by reducing stratification
   * Eliminate cold drafts on start-up

Like electric heating, hot-water heating is very dry. This is offset by ventilation, which introduces fresh air. A programmable thermostat is located in the forward passageway. In each living area, opening/closing individual radiators will control temperature manually.

In addition, to provide backup in the case of failure in a severe cold spell, a diesel bulkhead fireplace in the salon, such as the Kabola Old English Diesel Room Heater [4] or the Harworth Bubble [5] is also plumbed into the distribution system. Other types of bulkhead heater are available from Dickinson [6], Refleks [14] and Sigmar [15].Initially a fireplace was desired for lifestyle reasons, but as the design evolved it became a backup system. The Dickinson Bristol Diesel Cook Stove [6] in the galley can also heat the forward accommodation, but it is not part of the main distribution system. The main distribution system also routes through the towel rails in various compartments. These are switched out of the circulating water system in summer and heated with AC elements.