There are 10 key decentralized energy systems based on renewable energy solutions that have been identified for application in Small and Medium Enterprises (SME) hotels.
1.Biomass: Installations are available from around 15kW upwards, there is no significant technological upper limit to installation size. Pellet boilers are available with either a built-in hopper, filled manually with bags, or with a separate, bulk storage hopper. The latter allows pellets to be delivered by tanker, down a long pipe, typically just once a year, with the minimum of disruption.
2.Combined Heating and Power: CHP systems are typically run as heating appliances, providing space heating and warm water in hotel buildings like conventional boilers. The use of CHP would allow a hotel to produce electricity onsite at a lower cost and benefit from the heat produced as a byproduct of the generation process. A CHP system makes better use of the fuel put on them, saving up to 40% of the energy in total.
3.Geothermal Energy-Ground Source Heat Pumps: Ground Source Heat Pumps are one of the most efficient systems available today, with heating efficiencies up to 70% higher than other heating systems and cooling efficiencies up to 40% higher than available air conditioners.
4.Solar photovoltaic electricity systems: Photovoltaic materials have the ability to generate a current of electricity when exposed to light. Photons, which make up light, knock electrons of the photovoltaic material, creating an electrical current. Hotels can install PV panels to reduce or eliminate their monthly electricity bills and provide pollution-free electricity to their guests. The electricity produced can then be used to power a hotel or be fed back into the grid.
5.Solar thermal energy – Solar COMBI systems: Solar combi systems are solar heating installations providing space heating as well as domestic hot water in hotels. The primary energy sources are solar energy as well as an auxiliary source preferably such as biomass, either direct or with a heat pump. One of the biggest advantages of using solar energy as energy source for cooling is that the maximum energy is obtained when the cooling load is at its peak.
6.Solar thermal energy – Solar COMBI+ systems: Solar combi plus systems use heat from solar thermal collectors to provide heating in winter, cooling in summer and domestic hot water (DHW) all year round. The cold is produced by a thermally driven cooling machine, a sorption chiller, which is fed with heat (hot water 70-100°C). The main benefit of using the solar thermal energy to feed the chiller is that, in general, the demand for cooling is the highest when the levels of solar radiation are high.
7.Solar thermal energy – Domestic Hot Water Systems (DHWS): Solar water heating systems use free heat from the sun to warm domestic hot water. An auxiliary heat, additional boiler or immersion heater, is then used to make the water hotter, or to provide hot water when solar radiation is not sufficient. The solar fraction is the percentage of a building’s seasonal energy requirements that can be met by a solar energy device or system This fraction will be optimized through the sizing of the system so as to reach 50% to 100% or even more to be used in other features like swimming pools.
8.Wind energy: Small wind energy systems are based on a rotor, a generator or alternator mounted on a frame, a tail (usually), a tower, wiring, and the electrical components: controllers, inverters, and/or batteries. There are two different ways of installing small-sized wind turbines: i) mast-mounted: these are free standing and are erected in a suitably exposed position, often around 2.5kW to 10kW in size and ii) roof-mounted: these are smaller than mast-mounted systems and can be installed on the roof of a hotel where there is a suitable wind resource.
9.Micro Hydro Power: Micro hydropower is a term used for hydroelectric power installations that typically produce up to 100 kW of electricity. A micro hydropower system can produce enough electricity for a small hotel.
10.Water Cooling: Deep cold water from a lake or ocean is pumped through a heat exchange which facilitates the energy transfer between the deep lake/ocean water and the internal hotel building closed loop, providing chilled water for a hotel cooling system. The process is very similar to using chillers in conventional air conditioning systems. The main difference is that the cold temperature is not achieved by evaporation of a liquid into a gas