Patio Cooling System Recommendation
for a Restaurant in Tampa, FL
A restaurant owner consults with Ventizio as a patio cooling engineering firm to determine what would the best system to ensure the cooling of their outdoor dining area. Our firm is tasked with advising them with a recommendation allowing the owners to choose between a micro-misting system and an HVAC system.
Parameters of the Case Study
The restaurant is located in Tampa, FL. The outdoor dining area needs to be cooled off twice a day, between 11:00 am and 3 pm, and between 5:00 PM and 7:00 PM.
Dimensions of the cooling area
The outdoor dining area is a rectangle of the following dimensions: 100′ (L) x 50′ (W) x 20′ (H). The area is covered by a permanent shading structure (pergola), open on 3 sides. The area is exposed to a moderate breeze coming from the nearby seashore.
The patio can accommodate 50 diners are a time.
Temperatures and humidity levels
- The average day temperature under the covered area (with no cooling system) is 83°F between June and September, 73°F between April and May, and 65-70°F the rest of the year. No cooling is necessary during the months of November to March.
- The restaurant owner wants to maintain a temperature range of 68°F-70°F.
- Relative humidity range: June-July: 77%-80% August-September: 85%-99% October-November: 77% December-March: 65%-70% April-May: 75%
- Initial investment budgeted by the owner: $20,000-$30,000.
- Target operating costs: $1,500 monthly (includes maintenance and parts replacement).
- Water usage: No counter-indications to micro-misting
- Noise levels: Federal regulations on acceptable dB levels. But obviously, diners’ comfort is a high priority concern for the restaurant owner.
- There is no room within the outdoor space to conceal the HVAC units. Any concealment would have to take up space from the dining area (with a loss of revenue), or the units would have to be housed inside the restaurant and ducts be routed to the outside.
Recommend the most suitable cooling system for the outdoor dining area of the restaurant, considering the parameters and constraints provided.
- Affordable initial investment, typically within the budget range.
- Easy to install without taking up much space.
- Will be used in combination with natural breeze to enhance cooling during the hot months.
- Adds slight moisture, a beneficial effect during the drier months.
- “No wetness” feature ensures diners’ comfort. Micro-mist (micro droplets) disperses within 3-5 feet.
- Needs to blow enough micro-mist to cool off diners during the high heat months (July to September).
- More limited control over temperature levels.
- Heating elements can be delivered included in the system but are optional.
- Initial investment: $5,000 – $15,000 (system cost) + $2,000 – $5,000 (installation cost).
- Operating costs (monthly): $100 – $250 (energy usage) + $150 (water usage + maintenance).
- Greater control over temperature levels.
- Consistent performance across different weather conditions and seasons.
- Can provide heating during cooler months, if necessary.
- Higher initial investment and more expensive operating costs (energy and system wear & tear).
- Requires dedicated space for installation, impacting the dining area and revenue.
- Louder than a micro-misting system, which may affect diners’ comfort.
- Initial investment: $15,000 – $25,000 (system cost) + $5,000 – $10,000 (installation cost depending on duct work)
- Operating costs (monthly): $400 – $600 (energy usage) + $150 (maintenance + labor/parts + cost of refrigerant)
Based on the information provided by the restaurant owner, and based on the cost models, the micro-misting system is the more suitable option for the outdoor dining area cooling needs.
- The micro-misting system falls well within the initial investment budget, has a lower operating cost, and its “no wetness” feature addresses one of the main concerns with misting systems. Micro-misting dries up 3-5 feet away from the nozzle, with no wetness on skin and surfaces.
- The micro-misting system is easier to install and takes up less space, which is a significant advantage given the space constraints in the outdoor dining area. An additional HVAC unit would have to be housed into a sound-proofed cabinet directly on the patio area, which would reduce the space available for diners by at least 1 table of four. This would generate a permanent loss of revenue for the restaurant.
- The possibility to mount, on the existing superstructure, the cabinets housing the nozzles and fans of the micro-misting system without any additional construction makes it a more attractive solution for the restaurant as no additional cost is incurred for a special build and construction materials.
- Lastly, over the past 10 years the cost of water has increased more slowly than the cost of electricity, and the cost of HVAC refrigerant has considerably increased. The EPA has changed the regulations governing the use of HVAC refrigerant twice in 3 years, which casts some doubt over the ROI of a commercial HVAC installation. Considering the current inflationary environment, the operating costs of the micro-misting system seem poised to be durably lower than the cost of operating an HVAC unit.