An apparatus, system, and method for controlling combustion gas output in direct steam generation for oil recovery. A direct combustion steam generator burns a fuel and an oxygen-containing gas mixture to produce combustion products including steam, CO.sub.2 and N.sub.2. Supplemental oxygen is separately supplied to the combustion steam generator to adjust the oxygen content of the oxygen-containing gas mixture during the combustion process in order to adjust the ratio of CO.sub.2 to N.sub.2 produced in the combustion products.

Apparatus for generating steam, the apparatus including a source of liquid water, an injector in flow communication with the source of water for injecting liquid water from the source of water at a pressure of at least about 10,000 psia, and an impact chamber having a contact surface onto which the injected water is contacted. upon impact of the injected water with the contact surface of the impact chamber, the injected water undergoes a virtually instantaneous phase transition from the liquid state to a gaseous state following the contact of the water with the contact surface, thereby generating steam.

Invented is a Resource Tower that uses water electrolysis to separate out its elemental and purified H.sub.2 hydrogen gas and O.sub.2 oxygen gas. These gases form a pressurized flow for electricity generation for distribution and transport to heights atop the Resource Tower. Core advancements of this invention are the use of fuel cells at the top of the Resource Tower to electrochemically combine hydrogen gas and oxygen gas to produce electricity, heat, and water. The Resource Tower distributes the electricity, converts heat and water to steam to generate additional electricity for distribution, and ultimately coalesces the steam back to water at a height. The water that falls under acceleration of gravity from atop the Resource Tower is used to generate additional electricity for distribution. In addition to multiple sites of electricity generation for distribution, the purity of hydrogen gas and oxygen gas from water electrolysis is retained and the water resulting from the Resource Tower is purified and potable for distribution.

A steam generator including a heating chamber for heating water to generate steam, with a sidewall of the heating chamber being a heating element. The steam generator may be installed in an appliance, and may be removably installed in the appliance.

A hot water supply device and a hot water supply system are provided. A controller actuates a circulation pump at a constant output and actuates a heating mechanism for heating by a combustion mechanism when an instantaneous hot water operation is started in response to a temperature drop of a fluid while hot water supply of a hot water supply tap is stopped, until a minimum drive time elapses. The minimum drive time is set based on a flow rate detection value of a flow rate detector under a condition that the circulation pump is actuated at a predetermined constant output and an instantaneous hot water circulation path is formed.

A water boiler with dual heating functionality includes: a hot water tank having an upper section and a lower section; the upper section is narrower than the lower section; the hot water tank comprises an instantaneous heating portion, and a storage heating section; an instantaneous heating pipe arranged within the instantaneous heating portion; a storage heating pipe arranged within the storage heating portion; a water inlet component in communication with a bottom of the hot water tank; a water intake structure in communication with a pressurized water source and the water inlet component; a hot water outlet pipe connected to a top of the hot water tank.