Herramientas Industriales, Inc. Renewable Energy Division specializes in selling the lowest cost possible renewable energy and hybrid electric power systems for independent and back-up power. We service the Puerto Rico andCaribbean area and we distribute the most known and advance brands in the field. All our systems are specially design and configure for its specific applications. We also offer a full range of “Hurricane Buster” grid connected PV systems with battery backup for emergency operation. These systems are available in Integrated Installation Packages that include all components that are not readily available in local electric supply houses, such as PV modules, inverters, array mounts, DC terminal blocks, DC disconnects, PV deep cycle batteries, etc. All systems are engineered to withstand 150 mph winds.

 

       

Sample Typical Installation.

 

THE GRID CONNECTED ADVANTAGE

There are basically 2 types of PV systems—stand-alone and grid-connected. Stand-alone systems operate independently of a utility grid and are normally used where no grid connection is possible, such as in remote areas or for portable highway signs, etc. Some stand-alone systems produce only DC power. Other stand-alone systems are designed to produce AC power. Grid-connected systems nearly always convert the DC power produced by the sun into AC power. The conversion from DC to AC takes place in an INVERTER. There are many types of inverters for a wide range of applications.

Prior to 2002, stand-alone PV systems were the most common, but since 2002, more PV generation has been attributed to grid-connected systems than to stand-alone systems. One reason for this transition is that fully-interactive, grid-connected, systems optimize the use of PV electricity. The reason for this is that when the grid is available for a fully interactive grid-connected PV system, none of the energy generated by the PV system is wasted. Any electricity generated by the PV system that is not used on site is sold back to the utility for someone else to use. In a stand-alone system, if the electricity produced is not used on site, it is wasted. Stand-alone systems are still very popular and cost effective in areas where no grid-power is available for residential and telecommunication systems

User-owned grid-connected PV systems come in several different categories. It is important to understand the differences among these systems.

Grid-connected, but not interactive, PV systems use the utility grid as an auxiliary battery charger. This kind of system is common in areas where the grid connection is only available for a few hours each day. The grid provides additional battery charging to supplement that provided by the PV system. These system do not SELL energy to the grid. They just purchase it when it is needed and available. The system batteries store the purchased or PV energy for later use. If excess PV energy is produced, it is wasted.

Fully interactive grid-connected systems can either purchase energy from, or sell energy to, the utility grid. Any utility interactive system that is programmed to sell electricity to the grid must meet very stringent UL listing requirements. These systems must be capable of monitoring the condition of the utility grid and automatically disconnecting from the utility grid if the utility grid shuts down. There are two types of fully interactive grid-connected PV systems, as shown in Figure 1.

Figure 1a shows a utility interactive PV system without battery backup. Whenever the sun is shining and the utility grid is powered up, the electricity produced by the PV system is first used by the system owner and any leftover electricity is sold back to the utility grid. If the grid goes down, the PV system must also shut down. When this happens, the owner of the system will be without electricity until the grid comes back on again.

Figure 1b shows a utility interactive PV system with battery backup. This system combines the best features of the stand-alone and the grid-connected systems by incorporating an emergency power output feature on the system inverter that continues providing power to selected circuits if grid power is lost. One set of terminals on the system inverter connects to the utility grid through the owner’s main circuit breaker panel. The other set of terminals connects to emergency loads. When grid power is available, this set of terminals will either send excess PV power back to the main circuit breaker panel or will use grid power to supply the emergency loads at night. If grid power is lost, this section of the inverter shuts down, but the emergency terminals of the inverter remain operational. When the sun is shining, power produced by the PV array is used for meeting the requirements of the emergency loads and for battery charging. As long as there are enough batteries, and as long as the PV system generates enough energy each day to meet the needs of the emergency loads, the emergency loads will be operable 24 hours a day while the utility grid is out. When the grid is restored, the system automatically reconnects to the grid and resumes normal operation.

The Hurricane Buster series of Integrated PV Systems are all based upon battery backup fully utility interactive operation. They were designed especially for those in hurricane-prone zones who would prefer to have the sun provide them with electricity rather than having to refuel a constantly-running fossil fuel generator. The array mounting systems for the UPSUI systems have all been engineered to withstand 150 mph winds, meeting the stringent wind load requirements of Southeast Florida .

All of the Hurricane Buster systems can incorporate fossil generation for additional backup power. One of our representatives can help you to decide whether using an additional generator makes sense for your specific needs.

Keep in mind that a fossil fuel generator CAN NEVER PAY FOR ITSELF, since it is only run when the utility is down. On the other hand, a utility interactive PV system will produce electricity every day over its lifetime, which can be expected to exceed 25 years. The PV modules in all of the Hurricane Buster systems come with 25-year warranties. Depending upon the rebates or tax incentives available, the UPSUI systems will pay for themselves before their lifetime is over. In some areas with aggressive rebate programs, the Hurricane Buster systems will pay for themselves in a few years. Furthermore, a 5000-watt PV system will eliminate the production of 175 tons of carbon dioxide over a 25-year period.

HYBRID SYSTEMS: CONNECTING A GENERATOR TO YOUR GRID CONNECTED PV SYSTEM

The systems have been designed to be connected to the grid so power can be sold back to the utility yet have battery backup for when there is a power failure. By adding a generator to the system all the advantages of a hybrid power system can be obtained. These include increased capacity to run motors and other peaking loads such as air conditioning, pumps and charging batteries for electrical long range vehicles. Herramientas Industriales, Inc. is an authorized Kubota Generator Dealer.

Ratios from 3:1 up to 10:1 can be obtained when a generator is used. In other words, when you run your generator for 1 hour you can get enough energy for 3 hours of electrical power. This can be increased by applying principals of energy conservation and reducing your energy loads by selecting energy efficient appliances and loads.

WHAT SIZE SYSTEM DO I NEED?

There are a number of factors that will affect your choice of system size, including your roof (or other available) area, your budget and/or how much emergency energy and power you would like to be able to provide.  The list of systems (link to system list) shows the energy and power available from each system.  Note that ENERGY and POWER are different quantities.  Energy is measured in kilowatt-hours (kWh) and power is measured in watts (W).  Energy depends on how long a certain item is operated.  For example, a 20-watt compact fluorescent bulb can be operated for 50 hours on 1 kWh of energy, whereas a 1000-watt hair dryer can only be operated for 1 hour on 1 kWh of energy.

The power available from a PV system depends on the Power Rating of the Inverter.  Our systems use either Outback 3600 W inverters or Xantrex 5500 W inverters.  Note that this power is NOT the same as the power rating of the PV array.  The PV array POWER determines the amount of ENERGY that the system can deliver in a day.

So the system POWER is important, because it determines how many and what types of emergency loads can be run simultaneously without overloading the inverter.

The system ENERGY is important, because it determines how long a particular combination of loads can be operated each day without using up all the electricity produced during that day by the PV array.

In particular, older appliances generally use a lot more ENERGY than newer appliances, so it may make good economic sense to replace an old refrigerator with an Energy Star unit, rather than to install a larger PV system to run an inefficient refrigerator.  In many areas, either the State, federal government or utility may have incentive programs to encourage the purchase of more efficient appliances.

The following table lists common loads that might get priority under emergency conditions.  Add the watts to ensure that your inverter will not be overloaded and add the kWh to be sure your system will generate enough electricity to meet your needs.

 

Load	Approx. Watts	Time On	kWh Used
Energy Efficient Refrigerator	300	1 day*	1.5 to 2.5
Microwave Oven	600	10 minutes	0.1
Small Fan	50	10 hours	0.5
Compact Flourescent Bulb	15	5 hours	0.075
Hair Dryer	1,200	5 minutes	0.1
Clothes Washer	500	30 minutes	0.25
Laptop Computer (plugged in)	50	1 hour	0.05
Desktop Computer	200	1 hour	0.2
Small TV	100	1 hour	0.1
VCR or DVD Player	50	2 hours	0.1
Cell Phone Battery Charger	5	4 hours	0.02