Installing PAFMAC to all 320 rooms in The Island building from the initial construction of the hotel.

Located on the West Coast of the Okinawa main island, Onnason is known as one of the top beach resorts in Japan. In August 2018, Hyatt Regency Seragaki Island, Okinawa, which is the first Hyatt beach resort in Japan, opened its doors in Onnason, specifically on Seragaki Island connected by a bridge from the Okinawa main island.

The hotel has two buildings, The Beach House (24 rooms) on the Okinawa main island and The Island (320 rooms) on Seragaki Island, with six restaurants, bars, indoor and outdoor pools, a lagoon, beaches, including spa and wedding facilities. The special feature is its location that offers a 360-degree view of the various seascapes. All rooms have balconies and up-close views of the Emerald green ocean of Okinawa.

Open the window and the sea breeze flows in. You can truly enjoy Okinawa, blessed with nature.

Okinawa is often seen as an everlasting summer, but it is unexpectedly cold in the winter, and there is a large temperature difference throughout the day during early spring and early autumn, so it is rather difficult to provide comfortable living space for all guests throughout the year.

Therefore, the hotel installed PAFMAC provided by NIPPON PMAC in all rooms in The Island building at the time of new construction. PAFMAC is an air conditioning unit with a built-in heat pump in a fan coil unit. It is a 2-pipe system that enables individual air conditioning. It is often implemented as a measure to improve the existing 2-pipe fan coil system, so it is a relatively rare case to have the system installed from the time of new construction. We spoke with Mr. Kinjo, the director of the hotel's Engineering Department, who has more than 30 years of experience in hotel facilities.

“Normally, central heating such as 2-pipe fan coil system and 4-pipe fan coil system is standard for hotel air-conditioning. In the 2-pipe fan coil system, hot and cold water created in a machine room such as a boiler room is transported to the guest room through piping and the fan coil changes it into warm or cool air, so cooling is available when cold water is flowing and heating is available when hot water is flowing.

On the other hand, the 4-pipe fan coil system can be offer both cooling and heating throughout the year by constantly flowing cold and hot water but it doubles the amount of piping which increases required space and also increases cost to produce cold and hot water at all times. In addition, the 4-pipe fan coil system requires a large refrigeration machine such as a turbo refrigerator of about 800 USRT, and it requires the accompanying installation of a cooling tower, chilled and hot water header, and pumps. So, it is very difficult to install those large devices in a limited space in hotels.

For our hotel size, the turbo refrigerator needs to be as large as a bus. The cooling tower needs a space of an entire residential home. If these machines are visible to the guests, it will not be aesthetically pleasing, and if they are indeed installed, covers or additional design would be required to hide them, which naturally increases construction costs. Especially for this hotel, all the locations including the buildings are designed in the limited area of Seragaki Island. So, in order to overcome this issue, we found the solution in PAFMAC and decided to install it in every room. Because of this decision, we were able to minimize the facility sizes of large cooling tower and refrigerator.”

By adopting the 2-pipe system, the refrigerator was reduced to about one-fourth the size of a 4-pipe system, and by installing this on a rooftop and unseen from to customers, the design of the hotel seamlessly harmonized with the landscape without losing the aesthetics of the hotel.

Individualized cooling and heating by PAFMAC, a solution to individual comfort needs in Okinawa’s climate.

Mr. Kinjo further explains the benefit of installing PAFMAC:

“To this day, we have not had any complaints about air-conditioning at our hotel. A big difference between the previous 400-room resort I worked at before, which had conventional 2-pipe fan coil system. From my past experience, even in Okinawa, where its considered tropical, there is a big temperature difference between the day and nighttime in early spring, so we tried to get by barely with just ventilation. Even then, we could not escape discomforting the guests because the decision for switching between cooling and heating was difficult.

It is often mistaken that there is no need for heating during the summer in Okinawa, but there is a need actually. For example, there are people who are sick or those who feel cold easily. When such a person asked me to turn on the heat because it was cold, I could only bring a blanket or individual heating equipment to the guest. PAFMAC provides solution to these problematic situations, and I believe it is contributing to improved customer satisfaction.”

He further mentioned that PAFMAC is also effectively conserving energy:

“Normally, the conventional 2-pipe fan coil system can maintain a comfortable room temperature by ventilating air during the in-between seasons, so some cost savings can be achieved, but the situation becomes slightly different for customers from abroad. Many of them feel hot easily and some people want cooling even in the middle of winter. When such a person comes during the in-between seasons and there is a request to turn on the cooling, the refrigerator must be operated in the case of a 2-pipe fan coil system. PAFMAC is able to provide solution to every one of these individual requests without the operation of the refrigerator, contributing to the great reduction of fuel costs.”

The hotel has implemented a centralized monitor for guest rooms, so it can observe the air-conditioning operation in all guest rooms. They discovered that some rooms actually have cooling on even during the winter, from December to January. In addition, the hotel integrated a system where the PAFMAC will stop when the guest room window is opened to reduce costs further.

Mr. Kinjo explains that even after 1 year since opening its doors, PAFMAC has not had any breakdown or malfunction.

“I’ve been informed that the failure rate is low for PAFMAC, but we are simulating how to respond in case of failure, just in case. We have several PAFMAC reserves at our hotel, so we would like to demonstrate how much time can be replaced by our own maintenance staff. If there are vacant rooms available, then we can just change rooms for the guests, but I would like to test out whether we could change the equipment between check-out and check-in period, or when the guests our out of the hotel during the daytime, for when the hotel is fully occupied.”

Apparently, the hotel is fully prepared for the “what if” as well.

At the end of March 2020, Naha Airport’s 2nd runway is scheduled to commence operation, which would inevitably bring increased number of tourists from within Japan and abroad. Strategies to take lead in the increasingly competitive hotel market is essential. In Okinawa, where conventional 2-pipe fan coil systems are the mainstream, the introduction of PAFMAC, which provides a comfortable guest room experience, will be one of the differentiating factors that will overcome the competition.