Abstract: A hot water tank comprising a sleeve, a removable top lid, at least one changeable water holding compartment adapted to be stacked vertically within the sleeve, stacked compartments being connected by a connecting pipe and at least one heating means provided with one of the compartments. The changeable compartments are configured to be removable from the sleeve upon removal of the top lid in case of failure and the space between the sleeve and the changeable compartments is adapted to hold the contents of the compartments during a leak.

Abstract: A method for controlling energy systems such as multiple boiler systems to meet an energy need includes a controller configured as a sequencer with the remaining controllers act as individual boiler controllers which periodically send status messages to the sequencer. The energy need is determined by measurements at the sequencer which maintains runtimes of the boilers. The sequencer periodically sends control commands to the boiler controllers to add or delete boilers. The control commands give consideration to the run times of the boilers.

Abstract: A multi-stage heating apparatus having a first stage combustion chamber, a second stage combustion chamber, a primary porous matrix chamber disposed between the first and second stage combustion chambers, a secondary porous matrix chamber, heat exchanger tubes for transfer of heat from the combustion products to a working fluid, a recirculation device for recirculating combustion products in the first and second stage combustion chambers to the root of flames therein. A mixture of fuel and primary oxidant is introduced into the first stage combustion chamber, and the products of combustion therein are conveyed to the porous matrix chamber disposed between the first and second stage combustion chambers. After undergoing intensive heat transfer in the porous matrix chamber, the cooler products of combustion flow into the second stage combustion chamber forming additional products of combustion.